Choroideremia: a unique retinopathy

Published on September 29, 2022   32 min

A selection of talks on Ophthalmology

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Good day. My name is Ian McDonald, I'm the Acting Chair of the Department of Ophthalmology and Visual Sciences at the University of Alberta in Edmonton, Canada. I'm pleased to speak with you about choroideremia: a unique retinopathy.
Here's the outline of what I'm going to cover. An introduction, the clinical manifestations of choroideremia, its differential diagnosis, histopathology, electrophysiology, some of the cell biology, the genetic analysis of choroideremia, and clinical trials and potential therapies.
Choroideremia is a progressive degeneration of the retinal pigment epithelium, the retina and choroid. Ludwig Mauthner, an Austrian ophthalmologist, first described choroideremia in 1872. He believed the condition represented a congenital absence of the choroid. Importantly, Mauthner indicated that choroideremia should be considered a separate diagnosis from retinitis pigmentosa. Choroideremia is uniquely a human retinopathy as there are, to my knowledge, no naturally occurring animal models of this disorder. It is relatively rare, affecting one in 50,000 individuals in a general population, and is present in all races and ethnicities. Choroideremia is usually not associated with syndromic features, such as sensorineural deafness or myopathy. It is an X-linked disorder, and for that reason, a man affected by choroideremia will pass it on to all his daughters, but none of his sons as they inherit his Y chromosome. Female carriers of choroideremia can be identified with distinct fundus features usually seen by examining the fundus with imaging techniques that I will show later.