Quiz: Constricted Visual Field

A 40 year-old man presented with constricted visual field. He found himself easily bumping into people while walking on the street over the last 6 months. He also had difficulty seeing in the dark. His best-corrected visual acuity was 20/20 OU. Slit-lamp examination was normal except for mild posterior subcapsular cataracts. Fundus examination showed bone-spicule pigmentation for 360 degrees in the mid-peripheral retina bilaterally. He was clinically diagnosed as retinitis pigmentosa (RP). His mother and maternal grandfather are also affected. He found an online advertisement for a free testing panel of over 250 genes for retinal dystrophy and decided to have this test with the assistance of his general ophthalmologist. The results showed variants in 6 different genes. The patient is referred to you for interpretation. What could it be?

The lab’s gene testing report included:
ABCA4 gene, one missense variant –previously reported pathogenic
ABCA4 gene – a second previously reported pathologic missense mutation
EYS gene, one not previously reported– significance unknown
RHO gene, one frameshift variant – not previously reported, downstream frameshifts predicted to cause RP
USH2A gene, one missense variant  – not previously reported, possibly pathologic by predicting software
CEP290 gene, one missense variant, previously reported as disease causing
CRX gene, one variant – previously reported benign

 

Last Updated: September 12, 2022

3 thoughts on “Quiz: Constricted Visual Field”

  1. Please correct me if I’m wrong—> mutation of ATP binding cassette subfamily A (ABCA gene) is also seen in stargardt disease.

    Reply
    • Mutations in ABCA4 cause a number of phenotypes (phenotypic heterogeneity) including Stargardt, cone dystrophy, cone-rod dystrophy, RP and others.

      Reply

Leave a Comment