During this ocular genetics workshop, funded by a medical education grant from Biogen, various patient cases are reviewed and discussed by a global panel.
Panelists: Dr. Alex Levin, Jenina E. Capasso, Dr. Thales A. C. de Guimarães, Dr. Michelle D. Lingao & Dr. Nutsuchar Wangtiraumnuay
[Alex] Sure, thank you very much. Hunter is the medical director of Orbis and we have Noelle in the background who’s been really instrumental in putting this all together. This is a labor of love and trying to bring ocular genetics to the rest of the world in an accessible way that Hunter will tell us more of.
I want to introduce my co-panelists. Jenina Capasso, worked with me as a genetic counselor, now the director of the Ocular Genetics Program here at the University of Rochester. She’s a genetic counselor. Thales de Guimarães is a research fellow now at Moorfields Eye Hospital after having finished a fellowship in ocular genetics. Mich Lingao is in the Philippines, also fellowship trained in ocular genetics. And we have Nutsuchar also known as Abeer Wangtiraumnuay who’s in Thailand and an ocular geneticist there. Welcome all and thanks for your contributions. Hunter, I’m going to pass it back to you.
[Hunter] If we go to the next slide, I want to take a minute to talk about Orbis. I think most of you know about Orbis. We are a global non-profit that is focused on eye care. We’re really about technology and training. And Cybersight is the crown jewel for our platform for technology and training where you can go to Cybersight, you can see former webinars and resources from Dr. Levin, you can do E-consultations with experts from around the world. But really what I want to make sure is that you see this as a resource for you all in your communities and your networks. That this could be a resource to educate your colleagues about ocular genetics, to set up referrals so that patients who come to you have organized histories, all their lab work and testings are organized in chronological order, and you have a secure and safe way to communicate consultations going forward.
Actually Cybersight was started by a pediatric ophthalmologist, Dr. Gene Helvesten almost 20 years ago. And this is when digital photography was just getting started and we couldn’t get high resolution photos of the retina and the internet was slow. And so a lot of it was for strabismus and looking at oculoplastics and external disease because that’s what the photography and bandwidth allowed. But over the last 20 years we’ve really evolved, where now we have artificial intelligence that can be used for diabetic screening, it can be used for glaucoma, macular degeneration, et cetera. We have over 20,000 consults and a large portion of those are pediatrics simply because it started off with the pediatric ophthalmic community with Dr. Helveston and continues today with Dan Neely.
And so one of the things that’s very exciting when, for example, Dr. Levin gives a webinar, we sometimes have over 100 countries participating live. And then other countries where the time zones are not convenient, can go and look at the webinar and ask further questions through the Cybersight Library. Really, Cybersight has become a global resource for pediatric subspecialists and for subspecialists, such as you all on this call, that are now really pushing the envelope of technology with ocular genetics and gene therapy.
With that I’m going to, again, say thank you. I want to thank everyone who is participating today. But knowing that today is really just the start of something that we hope to be growing in 2022 with all of you participating as contributors and participants of Cybersight. Alex, thank you again, and Noelle, a huge thank you for all that you did to get this off the ground.
[Alex] Thanks very much, Hunter and thanks all. Our goal for today is to demonstrate the power of Cybersight. Our uber goal is that the ocular genetics consultation service of Cybersight will grow. We have ocular geneticists trained all over the world in any region they can go consults. And I want to show you a little bit how consults work. And this is an opportunity to do a one off or we even love it when we have ongoing conversations with our users. And as you can see, over 50,000 registered users in 200 countries that ocular genetics consults are rare and we’re trying to build that part of our profile, especially at this time when ocular genetics is really taking off in ophthalmology as a new speciality.
I’m going to take you to the first case. And to do this I’m going to take you to the website. The Cybersight website has multiple resources in it. And I’m just going to put in my password and show you what it would look like as you’re signing in. This is going to take me to my page, hopefully. And these are cases that have come to me that I’ve been asked to consult on. And we’re going to go to new requests, these are my page, and this is what it will look like on my end. We set this case up in Cybersight.
If we look at this case, the writer, which could be anyone on this Zoom, would type in a history. This case was submitted by Dr. Lingao. Let’s just see. A 55-year-old male, night vision problems since childhood, peripheral vision problems noted at 20 plus years old. Already I’m getting a feel for the rod system being involved. Diagnosed with retinitis pigmentosa, also known as rod-cone dystrophy. Had some cataract surgery, had some complications, we don’t know what those are, with minimal improvement in both eyes. Family history is unremarkable, has some diabetes, controlled medications, and really no other significant history that we can see.
That’s the history I would receive. And then you would get to put in some information about the patient who’s now hand motion in either eye at 55 years of age. Who’s aphakic, and there’s opportunities to put in as much or as little information as you’d think relevant regarding your exam.
Then what happens is that the user can load in anything they want. And I think this case is good because it shows that we don’t need to have high quality, top of the line, digital, we can deal with what you’re dealing with, what you’re dealing with in the real bedside manner. For example, here’s a pedigree. Let’s just enlarge the pedigree. It’s hand drawn, it doesn’t have to be fancy. Let’s see, Thales, do you want to comment on this pedigree? This is retinal dystrophy. They’re from the same region in the Philippines.
Mich, Dr. Lingao, how much, what’s the population of these regions.
[Mich] Actually it’s very small. It’s just a tiny region separate from the mainland. It’s a little part of the zone, but it’s a very small region. Based on this pedigree we can actually say something about this thing.
[Alex] There’s no consanguinity shown but this suggests a constricted gene pool, right? That would contribute, perhaps, to an autosomal recessive disease. Thales any other thoughts on this pedigree?
[Thales] It looks like a recessive pedigree. The problem is marked with an arrow there, it’s on the third generation, the second one that’s affected. That’s why it’s painted. There’s also he has a second degree relative with a history of, I think it’s early onset cataracts, I can’t really read. Cataract?
[Alex] Yeah, 18-year-old man, yes.
[Thales] Which may or may not be related. It’s interesting to see that.
[Alex] Already from this pedigree we can get some information that’s very helpful as far as perhaps later on, and we can go back and we can take a look at the patient because the user in this case, Dr. Lingao, has loaded the pictures. Let’s just take some previews of the pictures here.
[Mich] Dr. Levin, I just like to comment regarding the cataract in the pedigree. Because that is what actually the relative say. When they say cataract, sometimes it doesn’t really come out as cataracts. We just write whatever the relatives say.
[Alex] The pedigree is just a story told by the family.
[Alex] And nothing is real until we see it ourselves.
[Alex] So here we see the optic nerve is here, we see some mid peripheral pigment around in both eyes. We can see it here and here. Let’s take a look at another photo, see if we can get a better image. And then we see this kind of dense pigment around the mid periphery, we see some optic atrophy, although it’s probably overexposed here, we see a better view of the picture. Dr. Lingao, you saw the patient, how would you describe his fundus?
[Mich] It’s not very clear in this picture, but there were some bony spicules at the mid periphery, sparing a bit of the phobia. There are also some pigmentary clumping in the mid peripheral areas. There seems to be also some type of atrophy in the middle part behind the foveal area. And very pale disc and, of course, vessel attenuation.
[Alex] Yeah. And we could get supporting studies. In this case we do have some OCT. Let’s look at that. Very interesting OCT. This is a timed domain. If this is what you have, this is what we have to work with. And that’s what we’ll do. And we can see there’s attenuation. Thales, you want to comment on this?
Here we get a better view, a more enlarged view, we can see the retina is thinned, the ellipsoid zone is virtually absent except in the middle. Retina is generally thin, overall. We have a thin retina, preservation of subfoveal photoreceptors, autosomal recessive pedigree. What testing did you recommend here, Dr. Lingao?
[Mich] In an autosomal recessive pedigree with the findings of possible inherited retinal degeneration, the most ideal tests would be an autosomal recessive panel. Although the most ideal would really be a targeted gene test. But in this case, a recessive panel would do. However, in this case there are only certain labs available in the Philippines that patients can afford. So that’s one of our limitations. In this case, what was actually requested was a panel of inherited retinal degenerations. We see here a lot of variants of uncertain significance. That’s one of the disadvantages of really getting a big panel, especially inherited retinal degenerations. You say variants of uncertain significance, it means that these variants, we’re not really sure if this is the cause of the disease or not. That’s where genetics comes in now. We would want to have different steps in identifying or knowing if these variants are really pathogenic or not. Some laboratories they say or they have some information about these genes and some laboratories don’t. And you’ll need to have further research regarding this.
One step that we can do about this is further phenotyping. We could do what we call segregation analysis. Meaning that we could take a look more closely at the other family members and see if the findings in the family members is the same as the patient and see if they have similar variants. One thing in the pedigree we saw was that this patient had a nephew who had a cataract, it could really be good for us to be able to see what that patient has. And probably compare it with our patient.
Another thing that we can do, agin, research on these genes and see what type of mutations they have. It’s actually all written here, the different types of mutations. It says here zygosity, which is heterozygous. Meaning only one allele or one copy is affected. But because when we see a lot of variants, like in this case, there are different steps on how to see if the variant is really pathogenic or not. One is by segregation analysis, as what I mentioned earlier.
Second is taking a look at the different mutations and seeing which proteins are involved. Because for some mutations, some proteins or some disruption in certain types of proteins are actually more deleterious or pathogenic compared to others. It would also be good to access databases. We would start having the ocular genetics modules here at Cybersight and there would be a very good, there’s actually a very good way of doing testing or looking at the results of test in a step-by-step manner. Access to databases, so we have databases that we look for to see if a certain mutation or a certain VUS or variant of uncertain significance is really a mutation or not.
[Alex] I want to get back to the larger panels later. I will note this is a 328 gene panel. And these large panels, although they’re free, quote/unquote, to the patient, someone’s paying for it and that is the companies. And the companies are paying for this because they want to capture these patients for later gene therapy. There is a price to be paid and maybe Jenina you could comment on just a first glance how you would interpret these seven genes worth of errors, can you make a comment on that Jenina?
[Jenina] Sure, one thing that I’ll first point out is that when a variety is classified as uncertain significance, it’s not a diagnosis. It just means the lab found a variant, it’s different from what the norm is, but they don’t know if it’s disease-causing, but they can’t say it’s benign. They feel obligated to report it. That’s one limitation as you look at these variants.
The other is that, we’re thinking about an autosomal recessive and Mich, Dr. Lingao, talked about this. When you’re thinking of autosomal recessive, you’re looking for either a homozygous variant, meaning a variant that’s present in both of the two copies. Or compound heterozygosity where you find two heterozygous variants in the same gene. We’re not seeing that here. And the other question I have is looking at this laundry list of genes, do any of them actually fit the history and exact phenotype in the patient that we tested? In AIPL1, is that disease onset with just night vision problems in childhood with no peripheral vision until their 20s? That’s what I would want to know and maybe research about every gene on this list.
[Alex] Yeah, you have to fit the phenotype and also, these are autosomal recessive disorders and we only have one chain.
[Mich] One copy, yes.
[Alex] There’s a lot of reasons if these tells us that this doesn’t fit the patient’s disease. Another way to have gone about this patient’s testing, if it was available, would have been to say, well, is there any systemic findings associated? Did the patient have polydactyly that suggests Bardet-Biedl, et cetera, and narrow down. Or we could have said well this is the Philippines, in this region what’s the most common cause of RP in this region? And in the literature you can often find a paper for any given country that will tell you what the most common genes are. And then you can test the most common genes and forget, or at least limit, what’s called the false genome rate which is all of this stuff that comes out of anybody.
I test 328 genes on anybody you’re going to get all these changing. This case is just to give you a little taste of the power of E-consultation. We’re going to go into more detail on other cases. But what would happen, just to show you, is I get an opportunity to write a response if the counsel was to me. I might say, is there any systemic findings? I might say do we know what the genotype is? I might say what other testing is available? And I might say well, is there a way that I can help find additional testing or help you get a diagnosis on your patient? And then after putting this in, there’s an opportunity for the user to feedback to me the answers to my questions, any additional images or whatever. And that dialogue can go back and forth until the case is eventually closed and to get to the best resolution possible.
We could even get into subjects like support group for the family, we can get into the idea of accessing an ocular geneticist in the patient’s area. Who’s the closest person? And even to gene therapy trials if that’s appropriate for a given patient. This can go on and on, this conversation, in an endless fashion and to develop a back and forth to help you interpret complicated tests and we’ll see more of that in these other cases.
I’m going to move on and we’ll go into some of the points that were raised in more detail. That’s an introduction to Cybersight.
Let’s take another case.
Dr. Wangtiraumnuay, this is your case from Thailand, a seven-year-old. And we’re going to present this in the standard Powerpoint format, just for ease. And you told us about this child who presents with blurry vision in his glasses. And it looks like his best corrected visual acuity is 20/200 in each eye. He was -13. At seven years old he -15 in each eye. He was preterm at 30 weeks, 1400 grams, no history of ROP. Twin A died. And no nyctalopia, otherwise seems essentially well. What were you thinking, Dr. Wangtiraumnuay at this point in time as far as a diagnosis?
[Nutsuchar] Okay. This boy came to me that he has very high myopia in both eye. And his vision, unable to correct until 20/20. At first I think he has amblyopia. And of course he has very high myopia and he has the history of preterm. I asked about the history of the ROP also, passed out of course of the high myopia. This could be retinal dystrophy, retinal vitreopathy, or ROP post laser, or just simple myopia.
[Alex] You’ve got a broad differential diagnosis. You might want to look at the rest of the patient. Let’s do that, let’s look at the eyes first. Anything you want to point out that you see here?
[Nutsuchar] Actually, at first when I see this patient, I think it looks normal. But if you see after dilated, it might be hard to tell, but the iris is quite smooth. The crypt is less than regular. And actually he has the faint PSC in the left eye too.
[Alex] He’s got a featureless iris, doesn’t he? Really not a lot of crypts and valleys. Pupillary rough, even dilated is not really very obvious and that may be helpful because there are some disorders that have a featureless iris like that. A little PSC. And the fundus, can you just describe to us what you’re seeing here?
[Nutsuchar] Okay, this is a fundus photo taken by optometrist. The optic nerve is like mild, pale and dragged disc. Both eye, vessel attenuated. And the foveal is hard to see foveal light reflex. And I can see the choroidal vessel, like my tigroid fundus too.
[Alex] Also I can see here that the tigroid fundus seems to be, vessels are almost radiating out of the middle here, we don’t see the fovea real well. A lot of white without pressure, some other vitreal retinal abnormalities out here. And I think we’ll see on another slide, we might be able to see those vitreous. Let’s see what you found.
Here’s the pedigree. Any comments on the pedigree? Dr. Jenina, do you want to comment on the pedigree?
[Jenina] Sure. It looks like we have our proband. And a twin that passed at birth, so we may not have much information on whether or not they would have had myopia as well. And then two other siblings, both males, brothers who seem to be unaffected. And I’m assuming older than this individual. And then we have, at least generally, a relatively smallish family when mom has two siblings, dad has three. Nobody really seems to have anything that they’ve reported to us. So it seems like an isolated case.
[Alex] I think that it’s a good opportunity to think about high myopia, that’s pretty common in the general population. Myopia is very common. High myopia at this level at this young is very unusual. And although it can be autosomal dominant, we don’t have a parent with high myopia. It seems to be isolated to this child.
But let’s just think about the inheritance patterns for a single affected male in a family. If we just go through, maybe each of us can take one. I’ll take dominant. Could be a de novo mutation in a single gene that just occurred in this individual with neither parent being a carrier. Although it could be dominant with a parent that is low expressing, doesn’t even know they have the disease or non-penetrant. Those are less common but certainly can happen. How about you, Dr. Lingao, while he’s sorting out his?
[Mich] Yes, it can be anything. Can be recessive, can be X-linked, can be any type of transmission.
[Alex] That’s right, so a single affected doesn’t tell us-
[Thales] Can you hear me?
[Alex] Yes, now we can hear you.
[Thales] Sorry, sorry.
[Alex] You can see that it can be any pattern of inheritance. We see over here the preterm, no ROP, there is a vitreous strand that was seen in one eye. There’s evidence of a vitreoretinopathy. And Dr. Wangtiraumnuay, do you want to just comment on your differential diagnosis?
[Nutsuchar] Yes. Because he has a history of preterm and high myopia, I think it’s possible to have ROPER or ROP because has dragged disc too. The uptoss can be hard to see until periphery, that’s the first differential diagnosis. Also is the-
[Alex] Just so we know, ROPER is essential ROP with the exudative retinopathy. Very rare combination.
[Nutsuchar] Okay, the second is the Marfan syndrome that’s quite typical in Thailand compared to other high myopia syndrome. But in this patient, doesn’t have limb dislocation and the height of the patient is not high. Also the Wagner, Stickler and Knobloch’s would like to see their vitreous and are there systemic findings? So that’s why I’m looking for other findings in the body of the patient.
[Alex] Yes and Cohen syndrome is another one with high myopia. I think that the point here is in a high myopic patient, we should be thinking about systemic findings in the patient and take a look at the rest of the patient. We want to think of the family history which I wouldn’t say is non helpful, it’s helpful to know that no one else has it. And the rest of the eye exam. Let’s look at the rest of the patient here. What do you find there?
[Nutsuchar] This patient has occipital lesion. It’s like a mass but he’s otherwise healthy. He can walk, he can run, otherwise healthy, just a mass like this.
[Alex] Is it fluctuant?
[Alex] No, okay. There’s no hair over it, so there’s an area of alopecia over this mass in the occipital region. That may be important. That raises Knobloch syndrome, right, which is the classic association of high myopia. And I would say just here, having uncorrected vision at 20/200, that would be too severe for amblyopia. And that choroidal pattern, choroidal bearing so to speak, coming out, radiating from that fovea. Those would support this and it is a vitreoretinopathy. Let’s look at what else we have.
Dr. de Guimarães, do you want to comment on the appearance?
[Thales] Can you hear me now?
[Thales] Okay, sorry about that, big headphones, I had to change my microphone. There should be a beautiful high palate raise and enlarge nasal root. The ears they might be offset a bit, I can’t really tell by this picture. And there might be a little of an extotropia in the right eye as well, which may be just the photos that are fooling me, but that’s what I can see.
[Alex] I would also ask, does he look like a typical Thai boy? You have to consider the ethnicity of the child. He doesn’t really have the exorbitism, a pseudo proptosis, so to speak, that we see with Stickler syndrome. His eyes are well-set within his globe. He had a cleft palate, which is interesting, and he has hearing loss as well. Dr. Lingao, do you want to comment on that? Got a lot of caries too, I’m seeing.
[Mich] Very high arch palate over there and very irregular teeth. And the presence of hearing aide also suggests the findings of Knobloch, one of the findings of sensory and neural hearing loss for this patient.
[Alex] And what’s interesting is, you bring up teeth. This is just dental caries. And there are some disorders of the teeth which are associated with retinal dystrophies like amelogenesis imperfecta where you have poor enamel on your teeth. That doesn’t appear to be the case here. The teeth that are remaining have good enamel. You always have to sort out the associated and the non-associated, the primary and secondary findings in syndrome.
But this occipital lesion is really kind of tell tale. Ideally you could test maybe just for Knobloch syndrome, or the cleft palate, the hearing, maybe a bit of the bases may make you think about possible Stickler’s syndrome. Let’s see how the testing came in. Here’s that vitreous strand here that you can see.
Here’s what was done ruling out Stickler. These are the tests. And Jenina, do you want to comment on the testing that we might select here in this patient? We’ve got a bunch of genes that are possible for our two differential diagnoses.
[Jenina] I know in our practice we try to minimize the number of genes we test and try to keep it focused on the phenotype information that we have. I think it’s reasonable to go for Knobloch and reflex to Stickler or it’s also reasonable in this case there’s enough about this patient to suggest either/or. You could do a Stickler panel, some labs offer a vitreoretinopathy panel that might be a little bit larger and include other genes that might be extra, so to speak, in this case. But that would also be a potential action, probably one of our lesser preferred, third or fourth choice.
[Wanacan] I do have some questions.
[Alex] Go ahead.
[Wanacan] Would it help if we do foveal ERG to differentiate between Knobloch syndrome and Stickler syndrome before?
[Alex] That would certainly be helpful because with Stickler it’s usually normal, Knobloch it’s usually abnormal. Vessel attenuation also supports Knobloch more than does Stickler. What you’re saying is a very good point is to narrow the phenotype by additional diagnostic testing if it’s available. We reported OCT findings with Knobloch that are not seen in Stickler, that would help to narrow this down as well. And there’s always the possibility you could have two disorders. And that is yet to be seen. The testing of the patient we don’t have the results yet. But this is a good example of the strategy of testing.
[Wanacan] What about do we need to do the FFA to see if the peripheral retina have a vascular area to outer wrapper?
[Alex] That’s another great idea. We have this mild dragging of the retina. I think it’s a great point that it’s hard to see peripheral non-perfusion. Never trust your eyes, you need to do a fluorescein, see if it’s out there. And that would also help us with our differential diagnosis. All of these ideas of testing further phenotypically to narrow down your gene hypothesis and thus avoid a large panel of tests, if you can and it’s available, will cut down your false genome rate and get you to better diagnosis. Of course there’s the management.
[Mich] Dr. Levin, I have a question. The fact that the boy has a lesion in his head, isn’t that more likely leaning on Knobloch’s? I mean, aside from all those other things?
[Alex] What’s unusual here is the dragging.
[Mich] It’s very rare that you have that very classic head finding.
[Alex] And we might, by the way, want to image that, make sure it’s not encephalocele. Which is full blown Knobloch you’d get an encephalocele, it can be as mild as just an area of cutis aplasia or alopecia in the back of the skull. You want to better characterize that lesion.
One comment that’s put down here, I’d be interested in the panelists thoughts, is avoiding contact sports leading to traumatic retinal detachment. What do you guys recommend? Do you recommend when you have vitreoretinopathy, which this kid certainly has, we know that, we just don’t know the exact type and until we have genetic testing. I’d like to take a poll. Do you limit a child’s activities? Let’s just go down the screen. What would you say, Dr. Lingao?
[Mich] It’s hard to limit the child, especially a five year old, a toddler. We really can’t tell that to a child to stop being a child. (laughs) It’s hard.
[Alex] What would you do, Dr. de Guimarães?
[Thales] I would definitely not recommend stopping any physical activities just because of the increased risk. The increased risk is higher in Stickler syndrome, and even then I wouldn’t recommend stopping doing things that he does. It’s just more life and it’s boring, might as well do whatever you want. And take care, of course, protective glasses and all that.
[Alex] Dr. Wangtiraumnuay, what would you do?
[Nutsuchar] Usually I recommend to avoid boxing or basketball, very contact sports that’s possible to have accident from that. But otherwise he can run, he can jump, like a normal child. But it’s easier to have retinal detachment.
[Alex] Thai kickboxing would be a bad idea.
[Nutsuchar] (laughs) Something like that.
[Alex] But I let kids be kids. I let them go and do whatever and tell them to wear eye protection. I think that if you’re in a country where kickboxing is common, you can certainly wear eye protection if that’s allowed. But really there is yet to be any clear evidence that being a kid and banging your head a hundred times a day like kids do, is going to cause any major change.
This child got glasses, there was some lattice. If it’s Sticker, and one of the values of having a ultimate genetic diagnosis is to be if he had type one Stickler, we would want to do prophylactic laser to prevent retinal detachment. If he’s got Knobloch, we don’t have as much evidence for that. If he had peripheral non-perfusion, we would want to laser that area. There’s certainly a lot of reasons to do this. And if this case was submitted to Cybersight, we could come up with a strategy for testing and maybe a resource for testing as well.
Are there any more comments on this particular case from anyone?
[Wanacan] I have some question. Dr. Levin, have you seen how often of the hearing loss? As a search we didn’t Knobloch syndrome compared to the Stickler syndrome?
[Alex] Much less common is Knobloch. But it has been reported. Stickler, this kid might have both. Cleft palate is much less common than it is in Stickler syndrome. I don’t have the answer here to know the final question. If he had a genotype which didn’t match the phenotype, we would pursue the genotype further until we had a complete match.
[Nutsuchar] I have a question. In this child, how often do you recommend to do EUA?
[Alex] I think it depends on what the child can do and what we find. I would complete his workup, looking for the peripheral non-perfusion as was suggested by Dr. Wanacan. I think that I would, if I’m lasering, if the kid had a Stickler phenotype and I want to laser that area and come back in three to four months to make sure that the laser treatment has taken well and all the areas are treated. It depends on what I’m treating. Certainly, if the kid allows a peripheral retinal exam awake, you can do a lot more. But at five years old, not many kids will. And he’d need to come back for that.
Let’s move on to our next case. As we go along you’ll see different levels of resolution in these cases.
This is another case from the Philippines. 19-year-old who has congenital cataracts and microcornea. We don’t know if he had microphthalmia or just microcornea. He had a pupilloplasty. Whenever I see that I don’t know whether it was for a post op pupil or a pre op small pupil, but he had dilating drops in order to be able to examine the posterior pole. And then six years old, has some glaucoma onset, glaucoma following cataract surgery by the new international classification system. His axial length is not too bad, he’s had an Ahmed. And what we see is there’s a nucleation of one eye for retinoblastoma in the maternal uncle, the brother of the mother. Dr. Lingao, what were you thinking here, what were your questions genetically in terms of this patient’s history?
[Mich] Yes, based on the history. The patient has congenital cataracts, he has microcornea. The first thing that came to my mind, probably also has microphthalmia. But at the time, actually the history I based it on what the patient said. I didn’t really see the patient when she was young. This was just based on the previous charts of the patient. And the axial length wasn’t really that small for the patient to be considered to have microphthalmia at the time. The presence of cataracts, microcornea, and glaucoma. I was also thinking that the glaucoma could probably just be secondary to the cataract surgery or the patient being aphakic now. And plus this person doesn’t have any other findings, on radio systems, or even on examination of the whole body. The presence of retinoblastoma in the patient’s uncle, it may or may not be related. We don’t know exactly, so that’s one of the things that we would also want to see. Yeah, can we move on to the-
[Alex] Yeah, I was thinking that this is a wonderful example of how we think in genetics. We have all of this stuff going on with this patient. And we really have to sort out what’s important and what’s not important. Cataracts are often associated with microphthalmia and microcornea. That would be the primary malformation. Glaucoma, in this case, appears to be following cataract and unrelated to the genetic question.
[Alex] And these parents, I’m sure, sitting there thinking I wonder if my kid can get retinoblastoma? She’s 19, she might be thinking if her kids could get retinoblastoma. But it’s highly unlikely if mom didn’t have retinoblastoma and 19-year-old didn’t have retinoblastoma, if that’s related in any way. Looking at this and trying to think how am I going to test this, to sort out what’s important. Miosis, for example, there’s a syndrome called autosomal dominant cataract miosis microphthalmia syndrome. But it doesn’t sound like this, the miosis was secondary, the operation wasn’t until four years of age. We can throw out some stuff and throw in some other stuff and maybe help us get closer to a diagnosis.
[Jenina] Is it also, can I ask, is it possible that the uncle’s, and again, I don’t know how old he is, how long ago this was before we had good diagnostic technology, but is it possible he had a really old cataract that might have been concerning for retinoblastoma? Did they just enucleated to be on the safe side?
[Alex] Yeah, it’s a great point. Pedigrees are just stories. And until we have records, until we see a patient, we really don’t know. We hear all the time all kinds of stuff from families that turns out to be completely unrelated. And sometimes you have a pedigree, it looks like it’s autosomal dominant. We saw that patient recently, and the whole part of the pedigree, except our patient, had an entirely different disease.
[Mich] One thing I’m thinking though, although the retinoblastoma, of course, is located in the chromosome 13. There are some genes though in chromosome 13 that may also result in microcornea or even cataracts. It’s very far off now that this patient may also have signs of retinoblastoma, but I’m just thinking along that line. Where in maybe far off it might, actually I’m thinking if a microarray in this patient would help, no? I’m not so sure about that though. It’s a possibility.
[Alex] You’re trying to connect them. Could be a balanced translocation that left a deletion here, maybe a different deletion or duplication here with our proband. I know that you’ve been involved on paper where we looked at microarray as a way of evaluating cataract. Can sometimes get some surprising deletions and duplications in genes which may or may not be related to the cataract. There’s different strategies to go about testing in this family to better understand and answer this 19-year-old’s questions about the cause of her disease and her risk to her children.
Any other comments, Dr. Wangtiraumnuay or Dr. de Guimarães?
[Thales] Just wanted to say how important it is to just realize how things can overlap. As you said, it can be based on this pedigree that we’re seeing, congenital cataract and microcornea, this can be a sign of a constellation of diseases that can cause this. And a constellation of genes as well. It’s very important to separate is this really microcornea, is the glaucoma secondary to the cataract extraction? I think this is all the design line of the thinking with this genetic head. Because sometimes these cases are just hard to separate.
[Mich] Also I’d like to add. One of the anterior segment findings in this patient, said of course the pupils are irregular. Probably also because of the surgery the patient had. Although it can really say that it can be anterior segment dysgenesis because like as in pedigree it should have other signs. Sometimes it’s really hard to diagnose when you see a patient that’s already an adult, and you don’t know exactly what would cause the anterior segment findings. That was actually what the mom of the patient told me that the other doctor was probably thinking of aniridia for this patient, that’s why he referred for a genetics consult. But it seems that the patient didn’t have any other signs of aniridia. Although the patient has nystagmus, but he doesn’t have any macular hypoplasia or any of those other signs of aniridia.
[Alex] And if he’s had a pupilloplasty, if you cut the sphincter muscle you’re going to get what looks like aniridia. Big open pupil. Once again, another example of sorting out what’s the wheat from the chaff. What’s the important stuff and what’s the not important stuff. This 19-year-old woman wants to know is her kid going to have cataract. She wants to know if her kid is going to have retinoblastoma. And we can help her sort that out with just the history alone.
Here’s her refraction. She’s got her tube in place, a mid-dilated, irregular pupil. Just correct topia in the other eye, so that rules out aniridia, not going to have unilateral correct topia in the other eye and mid-dilated irregular pupil. Pressure’s well-controlled, her eye’s not that long, 22 millimeters. And she certainly has no retinoblastoma or retinoma that can be seen. I’m feeling pretty good about throwing out the retinoblastoma, not to mention Jenina’s excellent point that there may not be retinoblastoma, based on the story. I’m feeling pretty good about throwing out the glaucoma as being secondary to the surgery. I’m feeling really good about throwing out the pupil as being related. So I’m left with a 19-year-old with cataract and microphthalmia. Question is, how do we test for that? Jenina, you want to comment a little bit on testing, genetic testing for cataracts?
[Wanacan] Before that I’d like to ask some question. What about the parent? Do we see any phenotype of the parent?
[Mich] Actually for now the parents, we weren’t able to get in touch right away with the parents. Unfortunately the parents hadn’t set up that appointment. It’s very hard for them to set up an appointment due to other issues. But that would be good, of course, to look at the parents.
[Wanacan] We suspected about anterior segment dysgenesis or even aniridia, we can just see the parents first and then we can just move on.
[Alex] Sure, if the parents are normal, it doesn’t prove that it didn’t just de novo start in the kid by a recessive or a dominant inheritance. But certainly, examining the parents is always a really important thing to think about. It’s so rarely accessible when they’re sitting there you can just put them up to the slit lamp. This is an adult, makes it a little bit more difficult. That’s another excellent point.
Do you want to talk a little bit about genetic testing, Jenina, for cataracts?
[Jenina] Sure. I think that there’s been a lot of genes discovered and I think that our knowledge for genetics of cataract is still in its infancy, a little bit, it’s growing. But the utility of testing is still not at the best. Certainly when it’s a for sure positive it’s extremely helpful in our ability to counsel a family. On recurrence risk, what caused it, are there any other systemic issues that we need to counsel them about or manage them for. But often, I would say more often than not we’re getting multiple variants of uncertain significance that we then have to try to interpret and track through the family. And when you test family members to try to interpret the significance of a variant of uncertain significance, it’s also important to couple that with a physical exam. And from my understanding, more often than not, especially if you’re going up in the generation and in older individuals, you’re more likely to find some sort of lens opacity. Am I correct in saying that?
[Jenina] So it could throw off the interpretation. Is it related to the cataract that was observed in this patient at a young age, or is it just typical for the family member’s age?
[Alex] I think the other question is if I was going to look at a cataract, it’s totally isolated. patient’s otherwise perfectly well. I’d ask myself why am I doing the testing? Family wants to know what the chances of having an affected child. I’ve never heard of preimplantation genetics diagnosis to prevent a pregnancy of cataract. But at the same time, parents have their choice, they can elect not to intervene with the pregnancy. But you’re going to tell the family to examine the newborn baby the first two weeks of life for cataract anyway and treat it. There’s been a lot of literature, by Chris Lloyd’s group in the United Kingdom, showing a lot of benefit from genetic testing, showing diagnoses, but I think that answer is still up in the air as to whether to do it. Dr. Wangtiraumnuay, do you have any comments on this?
[Nutsuchar] Yes. For this case, I think it could be autosomal dominant with SC or X-linked because cataract could be anything. Also the other finding could really help because he has cataract and glaucoma, could be Lowe syndrome, Nance-Horan, aniridia like anterior segment dysgenesis. Also rubella.
[Alex] These are all possibilities and certainly want to, again, look systemically to see if there’s anything that could tip us off in one direction or another. That’s another good point. But I still would say that if any of those, I could probably source all those out by history and then test specifically for that particular diagnosis. If you do a cataract panel, once again we see, similar to the first case, a lot of variants of unknown significance.
And I just wanted to point out. If you look to the right side of the screen, this is what the laboratory writes back. And if we just look at what these are associated with, you can get some information. ERCC6 is associated with autosomal recessive, we have a variant of unknown significance in only one copy of the gene. A different disease Cockayne syndrome, hearing loss, short stature, developmental delay, miosis, but this miosis appears to have been after surgery. At 19, it’s unlikely that she has Cockayne if she’s otherwise well. This gene here, we can see is recessive. Myofibrillar myopathy, we would absolutely know that this patient had that disease at 19. This one here, VSX2, that’s more isolated often with coloboma. And this one, autosomal recessive sponyloocular, she doesn’t have these diseases.
[Jenina] VSX2 isn’t that associated with true microphthalmia and I think based on this person’s exam it was determined she does not have true microphthalmia.
[Alex] She has microcornea, it would be…
I guess the question is where does the panel? The panel creates this false genome late, a lot of these we could have just figured out by examining the patient. And that’s one of the problems. This was free, quote/unquote, 103 genes. It was available. And being available means a lot of people are using it. The question is what do we do with the results? We have patients who come in with all this stuff and they think, “Oh, I’ve got Cockayne syndrome.” Well, she doesn’t have Cockayne syndrome, right? Because we can talk to the patient, examine the patient.
It’s a really complex question about should we do genetic testing if the genetic test that’s available is less than ideal? And that’s a tough question. In this setting, let’s just take the example. Dr. Lingao, this is what’s available to you, right?
[Mich] Yes. This is the only test that’s affordable, actually, for patients. Yes.
That’s where Jenina comes in. Counseling is very important in managing expectations of the patients and making them know that we may or may not have results that you expect. Again, patient expectations has to be managed.
[Alex] That’s beautifully said. That is so true, so true. And also, we might be able to develop with your country, research collaborations that are usually free, where blood could go and get under research paid system and they would report out as a CLIA-certified lab. A critically significant lab if a result is found and with more targeted testing. That’s another thing that Cybersight allows us and the global community, is to help each other find connections and links and find ways to get genetic testing all over the world that’s more accessible to patients.
Just want to show you this, which I think is interesting and thank you for sharing this with us, Dr. Lingao. If you look at all the genes that are on this panel, just picking through we can see that the patient doesn’t have a lot of these diseases. BCOR, he doesn’t have Best disease, he doesn’t have Stickler syndrome, collagen 2a1. And the harder ones are really important, the crystallin genes, that’s a little harder to tell just clinically. But we’ve tested for all these syndromes, here’s Norrie’s disease. Sure it’s associated with cataract, but you would know if the patient had Norrie’s disease. And not the mention that she’s a female and female carriers are not going to present with cataract microphthalmia. This is the price we pay, so to speak, for big panel testing. A lot of stuff that we really, it’s almost like the sacrifice we make.
But we’re going to show you some other cases here that get to a diagnosis. We didn’t get to a diagnosis here, which is fine. What would you do without a diagnosis? Examine your kid the first two weeks of life, don’t worry about retinoblastoma, glaucoma. You tell every patient that’s got cataract surgery, we’re going to screen them for glaucoma. And I think she didn’t get the answer she wanted. Based on the pedigree you might be able to make. How would you counsel her based on the pedigree alone, Jenina, as far as her risk of recurrence.
[Jenina] Based on her family history?
[Jenina] Well, there’s not much here to go off of. As a potentially isolated female, maybe some family history. I wonder if that uncle’s available to be examined. Maybe he has microcornea in the eye that he still has?
[Alex] Great point. Let’s assume for a second that you’ve got nothing and she’s the only person, alone.
[Jenina] Nothing, just her?
[Alex] Lone female. Dr. Wanacan brought in the idea of examining the parents. Let’s say they’re normal. How would you do genetic counseling for an isolated female of the family?
[Jenina] In this instance we still have to consider that every possibility remains. For her it could be autosomal recessive. It could be autosomal dominant with non-penetrance or expression, or de novo, dominant mutation in her. In which case the risk to her children is as high as 50%. I tell patients it could be lower, but without a gene diagnosis or a true understanding of what caused it it still could be as high as 50%.
[Alex] Or as low as?
[Jenina] Or as low as, if we’re dealing with autosomal recessive, she has children with someone who is a non relative, different ethnic background possibly, that even if I lose the gene pool even further, it could be as low as the chance of him carrying the same rare recessive condition she has is maybe 3% or less. Could be as low as that or lower.
[Alex] We counsel with a range and say examine the kid in the first two weeks of life. Prenatal testing is less reliable in terms of ultrasound. We might be able to detect an obviously small eye. But I found that cataract testing at high level ultrasound is a little bit unpredictable. And you certainly wouldn’t want to make a decision about a pregnancy based on that. And examine the kid in the first couple weeks of life and see what’s going on. Any comments, Dr. Wangtiraumnuay or Dr. de Guimarães on this case?
That’s a great example. That’s a great case of sorting out what’s important, trying your best to do genetic testing of what’s available to you, understanding that expectations have to be managed. And then doing counseling based on what you’ve got and doing the right thing for the patient with the limited information.
[Thales] Actually, Dr. Levin, I just forgot to say something. You said something about the clinical diagnosis and that is something that I always tell our patients, that the diagnosis is clinical. We do molecular testing that seems to confirm the findings and to see other things and understand the molecular cause and the pattern of inheritance and other things that come with genetic testing, including genetic counseling. But the diagnosis is clinical. On a case like this, yes, I think we would stay more with that, sorry?
[Alex] You’re okay, keep going.
[Thales] That we would treat more in the clinical findings instead of, even if the genetic test is negative, it doesn’t really change what we found in our exam.
[Alex] Yeah. We’ve had three great cases. All of these could have been done by Cybersight like the first case was. We’ve had a great discussion about patterns of inheritance, counseling of families, ways to test, how to interpret these tests with all these variants. We’re now going to move to more definitive cases. And we’ll show you also how Cybersight can help a consultation like this. Dr. de Guimarães kindly submitted this case and I’m going to let him present it. So go ahead, I’ll advance the slides at your command.
[Thales] Thank you, Dr. Levin. This is a patient, this is a British patient. He came to us with 20 years of age, he’s a male patient who was referred from his local optician and a diagnosis given by his local optician was of retinal dystrophy. On his history he has nyctalopia since his early teens, he never tried to get driving license because he always felt he had difficulty with dark conditions. But he only realized, believe it not, that he was bumping into people two months before coming to the visit. Otherwise he’s healthy, there’s no relevant past medical history. And that’s the pedigree of his family. Should I comment on it? Yeah, go ahead.
[Alex] Yeah, would you comment? Go ahead.
[Thales] Yeah, of course. The proband is marked with an arrow and he’s affected by as oft we call with retinal dystrophy. His mother has a history of long term nyctalopia. And she’s not clear about when that started but she felt she always had nyctalopia and she has the maternal grandfather of the proband, of the affected patient that was referred to us also has a long term history of night blindness and poor vision.
[Alex] And he’s deceased, so we’re not going to ever know what this was caused by. But poor vision and nyctalopia. Jenina, what are you thinking about this pattern here?
[Jenina] We have one male who’s affected, it sounds like the mother may be having some symptoms. I think this could be their dominant, could possibly be X-linked as well because we don’t see any male-to-male transmission that would confirm the dominant inheritance pattern. We just see a male who might have been affected transmitting through a female family member to the affected male. I think that is a possibility to consider. Maybe mom is manifesting female X-linked carrier.
[Alex] I think it’s important it’s a small family, right?
[Jenina] It’s also a very-
[Alex] A 50% chance she’s going to be a girl versus a guy. It’s an autosomal dominance still in play with variable expression. One’s that ruled out is autosomal recessive as less likely. I don’t know their ethnicity, whether it’s a small gene pool but there’s certainly no consanguinity that’s shown that would be a double bar between a couple.
[Thales] These are Welsh patients. British patients.
[Alex] That helps us a bit. We’re thinking X-linked, maybe dominant. Although what do you think about the onset, Dr. de Guimarães, at such a young age?
[Thales] I would actually think that the onset of symptoms is not for when we see the next picture it’s going to be a bit clear on the next slide. Yeah, I think that is not, it’s not really in terms of nyctalopia it’s pretty late. But I think it’s just because his vision was too good.
[Alex] He’s pretty young, again a dominant form of RP, that’s what I’m thinking. What are you thinking, Dr. Wangtiraumnuay or Dr. Lingao?
[Nutsuchar] He has a typical fundus finding of retinitis pigmentosa and could be autosomal dominant or X-linked recessive.
[Alex] Have you ever seen a dominant patient present with such severe fundus and such severe nyctalopia from such a young age?
[Alex] How about you, Dr. Lingao?
[Mich] It’s usually very severe for early onset of nyctalopia and a severe phenotype would lead us more to an X-linked transmission. So that would be good if we can take a look at the mom. Due to possible findings in the mom as well.
[Alex] And was the mom examined, Dr. de Guimarães?
[Thales] Yes, the only medical history that she has is of night blindness in early age and there was nothing in the rest.
[Alex] If we’re concerned that she is a manifesting carrier of X-linked RP, then we could do some studies on her. Her exam might show a tapetal sheen on her retina. An ERG might be modeled to decrease. Fundus auto paresis is particularly good to see that pattern of abnormalities that we see in carriers. How about your opacity, this is the program, want to talk about the OCT here?
[Thales] Yeah. On the OCT we can see there’s global thinning in the retina with a slight preservation of the ellipsoid zones in the various foveal region. But otherwise it’s pretty thin and you can’t actually see any ellipsoid zone. It looks like the center’s a bit more preserved than the midperiphery.
[Alex] One thing I really like is when you focus on the ellipsoid zone, sometimes it’s hard to see, but if you look at the outer nuclear layer. You can see the outer nuclear layer, the black thins out to nothing right here, thins out to nothing right here. There’s nyctalopia, there’s loss in the peripheral vision. It’s coming in and we’re just knocked out our photoreceptors to this area right here, essentially. The rest of the retina being fairly intact. Ganglion cell layer, form layer, nuclear layer, et cetera. It’s really an outer retinal disease. The fundus photo has shown us the retinal attenuation that’s characteristic of that. The 20/20 vision is characteristic of these preserved photoreceptors right here, that’s what we see in the film. It’s a typical RP picture, early onset. Pedigree, Jenina suggested was X-linked recessive. The question is, how would you test? Would you do any more diagnostic tests? An ERG? Fundus autofluorescence? How would you do your genetic testing?
Dr. Lingao, you would have to do a panel to get an answer, right?
[Mich] In this case, yeah, an X-linked panel would probably be good.
[Alex] Is that available to you?
[Mich] No, I don’t think so. (laughs)
[Alex] You’d have to do that big panel, right?
[Mich] Unaffordable. Affordable? It’s available but it costs much.
[Alex] So if you’re doing the 348 gene panel, Jenina, how good is that at picking up X-linked RP due to the most common gene, the RPGR gene?
[Jenina] You have to be careful and look at the actual technical assays of testing. Some large panels are not great at coverage for the open reading frame of RPGR. The 15th exon is a very highly repetitive sequence and on large panels where they’re using massive parallel sequencing, they don’t pick up that region very well. It’s often missed. There could be mutations there that could be missed by a large panel.
[Alex] That’s a great point. I’m thinking this guy’s got an RPGR but if I order a big panel, I’m going to miss it. If they don’t, technically they’re looking at that reading frame in that particular gene. In our practice, we would just order RPGR with analysis of the RPGR frame and just start with there, one gene and let’s see what this patient has.
[Jenina] Statistically, roughly 80% of X-linked RP is caused by RPGR. Half of RPGR patients have a mutation in the open reading frame.
[Alex] Wow, that’s important. Fundus autofluorescence, you want to walk us through this, Dr. de Guimarães?
[Thales] Yes, there’s diffused patches of hypo autofluorescence in the perimacular region. There’s a high para fluorescence ring in the perimacular region as well. And there’s a bit of a hyper autofluorescence spot close to the fovea, which was not supposed to be there as well.
[Alex] And we can also see the vessel attenuation in these vessels more. Almost not even visible. Fundus autofluorescence is good at showing that. RP, young onset, he had the constricted vision to 10 degrees, full field electra EM, iso electric, multifocal, extinguished. One could even argue that an ERG, you really didn’t need it. Although I’ve seen patients who look like this who’ve got normal ERGs from pseudo RP. In this case you’ve got a lot of symptoms, you know it’s going to be this. The question is DNA. He was tested by a panel, and sure enough. What does this say to you, Dr. de Guimarães?
[Thales] It’s a deletion of a single base and it causes a frameshift in a premature stop codon. Although the lab doesn’t really report how prematurely that is, but it’s supposed to delete the entire protein. Because that’s the first few bases in the first axon of our PGR.
[Alex] What you’re saying is it’s important to understand the result, right? You have to look up on databases to understand this. And we’re going to show that in the next case, but we want to know, does this really cause the disease? Or is this just a change that’s a variant of unknown significance or benign change? If it’s way upstream, if it’s early on in the protein and you’re frame shifting, and the rest of the protein’s going to be jumbled until it stops, you’re going to eliminate the protein. But you can’t just take what the lab tells you. You have to go and do the research to figure out. But this is a pathogenic mutation. RPGR was our guess and we got there through genetic testing.
Now that we have that, what’s your next step? Dr. Wangtiraumnuay, we got a diagnosis it looks like. What would you want to do with that diagnosis? What would you want to do with that diagnosis? If you had that abnormality in this patient, might you do some further testing on the family?
[Nutsuchar] Do segregation analysis to check what the mom have. Of course mom should be a carrier in this cases.
[Alex] The pedigree would certainly support that, right?
[Alex] And although it’s a small pedigree and there’s a 50% chance that she could have it just any change that her son has. If she had it, that would be strongly supportive and we could look at her to see if she has features of a lionized carrier, a carrier who’s expressing some signs of disease, we can’t test her father. Taking the result from this individual and going backwards or sideways in the family. Wait, why did I say sideways, Dr. Lingao?
Who else might you want to test? Let’s say the mother’s positive.
[Mich] Yeah, the brother.
[Mich] Oh yeah, sorry. It’s a sister.
[Alex] She might be a carrier too.
[Mich] A carrier yes. And get counseling.
[Alex] She might be having children. She might want to know, right? I would test the mother. And if she’s positive, which she’s likely going to be, test the sister. And then how would you consult these two individuals, Jenina, the male who’s got the mutation. Let’s say the female has it as well. How would you counsel them in respect to having children?
[Jenina] What we can do is give them the information. For an affected male, in order to have a son, he only passes his Y, so this is something he cannot pass on to future sons. But his daughters will all be carriers because he only has one X to give and if the RPGR variant is truly the cause of this RP, he will pass it to every daughter that he would have.
For a female carrier, theoretically she’s two X’s, one likely is very healthy and doesn’t carry the variant. With each child they have, they have a 50% chance they pass the X that carries the variant and 50% chance, on the flip side, that they pass the copy that’s healthy. In order to have an affected son, typically the way we’d calculate is they have a 50% chance of passing the X that carries the variant and then a 50% chance of having a male child, so a 25% chance, theoretically, of having an affected son.
[Alex] With each pregnancy.
[Jenina] With each pregnancy.
There’s one other thing and Dr. de Guimarães might be able to comment on this, that you might want to do having this result for this young man. You’re in the UK, what might you do there?
[Thales] For this patient, I am based in Moorfield, so there’s plenty of things going on at the moment. There’s a natural history study for RPGR, looking at patients with XLRP. And we just finished the phase one gene therapy trial for patients with XLRP. Mutuation’s on RPGR and we’re starting a phase three as well.
[Alex] Yeah, there’s several sites, we’re a site for an XLRP study as well. And this patient, if he’s able to travel, he’s in the UK and he might want to travel. If he’s interested and is explained the risk and benefits of treatment we can help them sort out what might be available and get him into a trial if he’s interested in participating. Carefully, as Dr. Lingao mentioned, managing his expectations, it’s a research trial. But we can offer that to patients now. Initial results of the RPGR therapies have been somewhat promising. That may be something we can offer.
On the flip side of this, there’s a lot of junk out there in terms of trials. Stem cell trials that are really not at the stem cell point in time. As far as therapy, but there’s research trials going on. But there’s also trials that have been shown to be very dangerous and very bad. We want to help the patient find the appropriate trial that fits their interest level, which may be zero or may be high, and offer that to them as well. That’s another advantage. We couldn’t do that without a gene diagnosis so there are some gene agnostic trials going on with stem cell and gene therapy to prevent degeneration. At least having this gets an entry point into the world of gene therapy.
And I would be very positive with these patients and say, “Look, 20 years old, you’re going to have a treatment. This is not a ‘You’re going blind,’ this isn’t a death sentence anymore. Treatment is available.” And one thing we’re working on with Orbis is trying to figure out ways to bring treatment to areas of the world that normally wouldn’t have that accessibility, in particular Thailand and the Philippines. And that’s certainly coming, that’s certainly coming. Low cost, affordable testing for areas of the world that might not otherwise have it. Any other comments or questions on Case four?
[Thales] Yeah, just two things that are very relevant that you and Jenina said. The first thing you said there might be, we may have done too much and that’s, I think, this is a really good case where it illustrates where it really overshooting things. There was no need for multifocal ERG and even if you don’t have access to FAF, to fundus autofluorescence, which trust me, a lot of countries in the planet don’t. You didn’t need to do that as well and the diagnosis is still very clear based on the family history and on the ocular findings.
And the second thing Jenina said about the ORF15, the part of the gene that’s very hard to sequence. And that’s true. I think the panel wasn’t really necessary because actually, Jenina, this is not a panel that sequences that area. If it was on that area with 50% chance we got lucky, it wasn’t me who did it, but whoever did this test got very lucky because he had a 50% chance of missing that mutation. I think it overshoots instead of asking as Mich suggested an X-linked panel or even going straight for RPGR since the odds are so high. And then you go for an RP panel with 170-something genes, which really may make a lot of noise. This is a typical case of overshooting and where targeted genetic testing would be much more relevant.
[Alex] But at the same time, with 200 countries participating in Cybersight, it doesn’t matter what you’re able to do in your own country. We could have gotten to a diagnosis one way or another with limited testing, with just a simple history, with whatever was submitted to Cybersight, and we could help you from any country, get to this diagnosis one way or another. And then do the counseling like Jenina so aptly recommended.
There’s a lot that we can do through this Cybersight portal that would get us to an answer or at least get the family to a place where they’ve got enough information to make decisions about their life and reproduction and so on and so forth. Any other comments, Dr. Lingao, Dr. Wangtiraumnuay?
[Nutsuchar] I have a question. If this patient doesn’t do any genetic testing, what will you recommend anything change?
[Alex] That’s a fantastic question, thank you. Because you might ask that, you might say, well, why even do genetic testing? Why do we do genetic testing? Do we do it to help confirm our clinical suspicion? In this case it could have be variable penetrance autosomal dominant. If we would have done a fundus autofluorescence if it was available on the mom, we might have been able to see the axon activation pattern in the retina. Or if we examine the mom, see evidence in the mom that she was an X-linked recessive carrier. We might counsel them that testing wasn’t available based on that.
The other thing is, we couldn’t get them into a gene trial without that testing, he’s not going to be accepted with the testing. We test to confirm our clinical diagnosis, to counsel the family the best with the optimum testing, and to open up access to gene therapy. But it isn’t absolutely necessary if we can satisfy the parent or the family or the child, whatever, demand, for information, we can inform that as best as possible in their setting. And I think there’s a lot to be learned from a case like this, even without genetic testing, you probably could have come to an answer.
Let’s move on to Case five. This is going to get us back to something we discussed early but with a different resolution. This is a case from here, a seven-year-old male presented with a solitary, dysplastic kidney now with stage IV kidney failure. And his visual acuity is 20/30 in both eyes, so he goes to see his eye doctor. And he’s otherwise well, he’s got a bad kidney and he’s got mildly subnormal vision. And when we look at his retina, we see he’s definitely got something wrong in his retina which led him to be referred to see us.
And what we see here, why don’t we let, Dr. Lingao, do you want to comment on this?
[Mich] Yes. There’s, well on the right eye there seems to be a small yellowish macular lesion which is actually much more evident than the left eye, which looks like the classic yoke-like macular lesion seen in the tell of form generations. And the other parts of the retina, mm. It looks okay.
[Alex] Yeah, vessels are normal, disc is normal. There’s a little bit of blood right here. A little hard to see, perhaps, from your screen. And this looks like more scarring, a little blood there as well. And a Best lesion here. Everybody happy thinking about Best disease here? Dr. Wangtiraumnuey, happy with that?
[Nutsuchar] Yes. This looks like typical Best disease.
[Alex] The question is, do you ever get a solitary, kidney dysplasia renal failure in Best disease?
[Nutsuchar] I’ve never seen the Best disease with kidney disease together.
[Alex] Yeah, I’ve never seen it. We looked it up, can’t find it, never been reported. Are we on to something really hot and new? Or is to true-true unrelated? That’s the question here. That’s a more blown up picture there, we can see the blood better. Here’s fundus autofluorescence, we see the typical of the tell of form egg-yolk lesion, hypofusion in the left eye. The right we can see the blood there, little specks of blood as well. Maybe a little bit of a hyper autofluorescence around the edges of the lesion that’s residual.
But when we do an OCT, what do you see here, Dr. de Guimarães?
[Thales] There’s a big subretinal lesion which is probably a deposit of lipofuscin.
[Alex] Yeah and in the right eye?
[Thales] The same, but it’s a bit fishy that I don’t really like that. (laughs) The aspect on the right eye. There’s a, I am not sure if you can say that I would definitely maybe do a fluorescence in this patient just because of the aspect of this right eye. Because I’m not really convinced that this might not be a CMV.
[Alex] Yeah, and I think it’s got that more vertical orientation of a CMV as opposed to this uniform dome here. You can see the subretinal fluid that’s in there, we don’t see the lipofuscin. But what’s really odd here is his vision is so good, I would have expected his vision to be bad here. But this is a subretinal neovascular membrane and it’s confirmed by fluorescein.
If you have two different diseases, we might be able to unify them by a microarray, looking for a piece of DNA that is duplicated or deleted, more than one gene is involved. But his microarray was normal. The next thing was we tested as two separate diseases. We tested his BEST1 gene for his Best disease. And sure enough that came back positive with a glutamine and alanine at position 653 of the DNA which causes an arginine to go to a histidine, heterozygously in position 218 of the protein, heterozygous in the DNA, missing the protein. Which the lab tells us is pathogenic. My question is do we have a diagnosis? Is there anything else that anybody wants to do, are you satisfied that we’ve got the answer and we don’t need to look any further? Anybody? Dr. Wangtiraumnuay?
[Nutsuchar] I think Best disease is autosomal dominant and the phenotype of the patient is pretty matched with the genotype. I’m happy with the Best disease.
[Alex] Yeah, and we might want to examine the parents because they may have mild affectation and not know. Just have an abnormal EOG and have a nearly normal examination. OCT on the parents may be helpful. But I think one of the things you want to think about is that the lab says that is pathogenic. How certain are we in what the lab says is right? And we often do a lot of expiration of the test result to understand is it truly pathogenic? And this is an example of the kinds of things that we go through on every patient.
I guess the lesson here is don’t order a test unless you know what to do with the results. But this is the kind of evaluation, we can look at what’s called the Grantham score, we can look at what this change in amino acids, how significant is it? It’s really not that big of a difference between arginase gene, it’s fairly low. But the position is conserved across species, it’s called a GERP score. We know that it’s highly conserved, any alteration may be more important because it’s position has withstood the forces of evolution. The CADD score is another thing, you can look it up on the internet. And CADD scores take into a lot of different variables into account to score the pathogenesis.
Population databases, a very rare change in the normal population that are using favorable pathogenesis. And it’s previously been reported in people with both autosomal dominant disease and autosomal recessive disease. It’s been submitted to ClinVar, which is a online database where it’s been caused pathogenic or likely pathogenic by other researchers. There’s computer predictions, in silico predictions, that say that it’s going to be deleterious, that’s the least reliable.
There have even been experimental studies on this particular chain to show that it affects protein function. We can look at other variants in the same position and it says it will mess up this position pathogenic. And then there’s the American, I spelled it wrong, ACMG classification system and we can use that. Everything is arguing that it’s pathogenic, even though arginine to histidine is not a big biochemical change. All of this evidence we can accumulate, helps us say we got it. To be sure. Dr. Wangtiraumnuay is absolutely 100% right, as she always is, this is Best disease. We got a mutation, the lab said pathogenic. We can say that’s pretty darn good but we’re going to go the extra nine yards, excuse the reference to American football, and we’re going to score the touchdown by getting all of the evidence that supports this change. Jenina, do you have any comments on that?
[Jenina] I do. I would just add that you pointed out some discrepancies, but if you look at some of the guidelines for variant classification that are available, a lot of them weight certain pieces of evidence a little more heavily than others. The physicochemical difference is something that’s not weighted as heavy as the experimental studies show. If there are functional studies published on a variant, that outweighs pretty much everything. The strongest piece of evidence.
CADD score’s not very high. The CADD score is an accumulation of a lot of in silico predictions and other things. The idea is that the number, positive numbers so anything over zero is trending towards pathogenicity. But the higher the number the stronger the likelihood that your variant is pathogenic. A 1.4 is not very high and isn’t something that would convince somebody that your variant’s pathogenic. But this is negated by the fact that there are experimental studies showing the fact of this particular variant on the protein.
[Alex] Maybe if you have the AC this should be ACMG classification. If you have that citation or something from 2015, you can just put it in the chat so people that are watching have that available, that would be useful.
Any other questions or concerns, what about his kidney disease? That’s not related. You’ve got another reason for kidney disease and we’ll leave that to our nephro geneticist to sort that out. But what we’ve done for this family is tell them that it is unrelated and that the progeny of this child may have Best disease, they may have a kidney disease, but they are unrelated.
Any thoughts or comments on this case?
[Wanacan] I do have some question. With a typical fundus finding of this kid, do you order him to do the EOG? Because it’s not easy for kids to do the EOG.
[Alex] The EOG requires a lot of compliance and there’s noise and that and so on and so forth. But if I have it available and the kid can do it, it’s another piece of evidence to help. In this case we have the unusual situation of that other eye with the good vision and face and the CMD. I like to hone down as much as I can on the phenotype. If you didn’t have an EOG in your country, that’s fine, you don’t need it. We got there without it in this case.
And Jenina just put that reference in the chat for the ACMG, that criteria for everyone.
Any other questions?
[Wanacan] I’m sorry, so that mean you ordered an EOG before you do the genetic testing of Best disease, correct?
[Alex] Yeah, in this kid we did. I believe. I think he was too young, if I remember correctly. He wasn’t able to do it.
[Wanacan] Would it be helpful if we just ordered the parent to do first and then if the parent have the EOG pattern abnormal then we just go for the genetic testing and spare the kid?
[Alex] You mean to test the parent?
[Wanacan] If the kid cannot cooperate to do the EOG, and fundus is quite typical, and when we do the EOG with the parent and each of the parent have the characteristic of the EOG of Best disease, would it be helpful to?
[Alex] You’re bringing up a very good point which is one thing that’s not on this slide is testing of the parents. Let’s say one parent had evidence of the disease. You could add another bullet point here of segregation and if the parent had the same change as the child, that would be added evidence that it’s pathogenic. You’re getting into resources, what’s available in your country, how much can you do. EOG’s the least reliable of our tests, it’s not the easiest test to do. And you can have a Best disease pattern due to other genes, IMG genes with a normal EOG. That wouldn’t help me, per se, I wouldn’t need to have that. It’s just accumulated evidence and we’re always trying to accumulate evidence to know that we’re right. What we avoided here was a big panel that would have gotten us all this false genome rate, we wouldn’t know what to do with. But I think in this case I would have just tested the child because it was so obvious. And we know Best disease is sometimes you can have it and not show anything. We want to be testing someone where they know they got it.
[Wanacan] Okay, thank you.
[Alex] You were going to say something, Dr. de Guimarães?
[Thales] Yes, quick thing first. Just to what Jenina was saying about in silico tests and that’s actually true. In terms of it’s not something that you would base your criteria on. And I think it’s something that adds weight to what you’re doing to see if it’s really pathogenic or not. We’re doing some retrospective reports here with some specific genes and the discordance is so high that you can’t even consider in silico to be usable on those genes. Any of those poly fan sift, you can trust in. I think the most important part would be the population databases and the conservation be as well and what has been reported in the literature. And yeah, experimental set is in protein function but just to leave it out there because in silico are really not that sensitive to these.
[Alex] I like to say you can trust them when you can trust them. In this case, everyone says deleterious and everything else is deleterious. But you’re right, it’s the least reliable piece of information.
[Thales] And I just wanted to say another thing about this that we usually see. What you see in the OCT and in the photos doesn’t really correlate with the visual function. That’s just another thing to leave out there. Sometimes you might have vision that’s very good to what you actually see, even with CMV. It’s just something to add.
[Alex] Two interesting things about this case just to add on. One, the child did have an injection in the right eye of an anti-VEGF and that region went away. He’s doing well, he’s no longer bleeding and his vision has been preserved. Number two, in our attempt to see could the kidney be linked, we looked at the expression of the BEST1 gene. And sure enough, the gene is expressed in the kidney. But we have no other evidence by prior reports. And that’s the advantage of large databases.
For example, we collaborate here with Ed Stone of Iowa, and between the two of us we’ve got over 70 years between us of doing this. And when neither one of us, we’ve both seen tons and tons of Best disease, have seen a kidney disease and Best disease, that kind of population incidence really helps you understand that it’s unlikely to be related as well. Even though the gene is expressed in the kidney. By the way, clinical trials for Best disease are being developed for gene therapy.
[Jenina] Another thing I’ll add, it’s unfortunate we don’t have the pedigree to show, but I do recall there was a family member with kidney disease that does not seem to segregate with any visual symptoms, as far as we know.
[Alex] That’s another important thing. We have a little bit of extra time, I think we’ll run through the last case just because it’s a good case, we can use our last 10 minutes.
Another case from here, 45-year-old female had a cone-rod dystrophy. I think we’ve said this before, everything’s just a story until you see it yourself. We have patients who come, I saw one the other day, that had four different diagnoses given by different doctors. And had multiple panel testing. And as a result of multiple rounds the parents said, “Oh, he’s got seven genes that are abnormal.” Well, obviously a lot of them will be variants of unknown significance. Part of the time we’re just sorting out from inappropriate use of genetic testing, where the confusion, and the first doctor said it was this and the patient keeps going on and on.
15 year history of slow, progressive blurring of vision since she was 30 years old. Had some trouble driving at night, difficulty seeing letters on road signs. Here’s her vision, 20/150, 20/40. In her fundus we see this geographic lesion, notice that there’s pigment on atrophy, characteristic signs of the disease. We have flecks of subretinal deposits around that lesion and extending out in the macular posterior pole in both eyes. There’s this kind of radiating pattern which sometimes makes us think of a gene PRPH2, pigmental atrophy and the geographic lesion makes us think more of ABCA4. The vessels are normal, disc is maybe a little bit pale medially.
We look at the fundus autofluorescence, we see a similar confirmation in our clinical findings. Dr. de Guimarães, do you have any comments on this?
[Thales] No, it’s just confirming what you see in the fundus photos and sometimes it gives you a much better view of what you see. You see the flex hyperfluorescence there and you see the very well-defined central atrophy in both eyes.
[Alex] What gene would you be thinking about here?
[Thales] Either ABCA4 or PRPH2.
[Alex] How about you Dr. Wangtiraumnuay?
[Alex] And you, Dr. Lingao?
[Mich] I would go for ABCA4.
[Alex] There you got it, you got three experts who look at a patient, they’ve got a history, they’ve got a fundus photograph, and they’ve got a fundus autofluorescence. And boom, they’ve come up with the same one or two genes. If you had to do a panel, you do a panel. But you still have your phenotype in your mind as how to interpret that panel. That panel of 300 genes has got diseases on it that have nothing to do with what this patient has. We throw those out. If we can do more focused testing, we can do more focused testing. And I believe that’s what was done here.
Here’s the OCT. Macular atrophy, we’ve lost our photoreceptors, we can see these lipofuscin deposits along the way here. The rest of the retina looks good, we can see the outer nuclear layer and the ellipsoid zone are peaking up outside the area of geographic atrophy. This is the opposite pattern of the rod-cone dystrophy that Dr. de Guimarães presented earlier and that Dr. Lingao presented as the first case. It is cone or central retina more than peripheral retina. But sometimes with ABCA4 you can get rod effects if you didn’t have an RP type of phenotype. We know that a symptom of nyctalopia isn’t going to dissuade us too much. Here’s the other eye, a similar picture.
And that’s what we did, we tested one gene. The lab tells us two pathogenic mutations. We know these mutations, they’ve been previously reported but we got a problem. The problem is how do we know these are on separate copies of the chromosome? ABCA4 are always autosomal recessive disease, we have two different mutations are needed. But they could be on the same chromosome and the lab doesn’t tell you that. Because of that, we have to test the parents to prove that they’re on separate chromosomes. Do you want to comment on that Jenina?
[Jenina] Yeah. In most cases, when you get variants back in a patient, you can look at the lab report. Most often they’ll even say that they cannot determine that the two variants they were reporting in your patient are either present on the same chromosome or separate or opposite chromosomes. ABCA4 is typically always autosomal recessive so you would expect that if these variants are the cause of this patient’s disease, they have to be present on two separate copies. One variant would have been inherited from mom, the other variant would be inherited from dad. In this case, the only way to prove that is to test mom and dad if available. In the absence of one or both parents, other first degree relatives, full siblings are usually the most informative to test.
[Alex] And we’d also want to make sure these changes are indeed pathogenic. We went through our whole thing again, looking at all these scores and tests that we’ve talked about. And we got to a classification that they are indeed both pathogenic, we’ve observed them before in our patient population. But this question remains: are they on different alleles? We’ve got a strong phenotype as Dr. Wangtiraumnuay has reported earlier, she said, the phenotype matches genotype. We still have to go the extra step to prove that these two pathogenic changes are on separate copies of the chromosome.
Genetic testing is complicated, there’s a lot of steps, there’s a lot of points in the testing in terms of interpretation that involves family history, history in the patient, looking at systemic signs, tossing out what’s important from what’s not important, and making sure your genotype matches your phenotype. And then helping the patient with clinical trials, with counseling, et cetera.
We’ve got four minutes left. Any questions or points from the panel? I just want to, before opening up, say this is what Cybersight can do. For anybody who’s listening to this, if you’ve got unsolved questions, there’s tons of genetic diseases out there as illustrated in this slide, that have ocular effects. Just for your interest, we’ve got ataxic telangiectasia at the top, fundus albipunctata in the middle, Lisch nodules in neurofibromatosis, we got Marfan syndrome at the bottom left, Alport syndrome bottom right, coloboma, Axenfeld-Rieger. All of these are genetic eye disorders, we can help you through Cybersight. And we’ve seen some of the expertise that our panelists have. If you’re sitting in Europe you’ve got Dr. de Guimarães, if you’re sitting in Asia you’ve got Dr. Lingao and Dr. Wangtiraumnuay. A lot of resources out there. Feel free to call upon us, we’re opening up this to the world, we hope people will use it.
Any other questions or comments from the panelists? I’m going to thank you guys, it’s great to see you again. Better in person, but COVID has allowed us to realize the value of Zoom. Thank you to Noelle for helping us put this all together, we couldn’t have done it without your help. Thank you to Hunter for making this all happen. We wish you all a great day and a great week and we remain available and I’ll keep you posted as further sessions like this become available. Thank you very much, guys, take care and be well.
November 30, 2021