Hereditary Retinal Dystrophies

Retinography (Clarus 700, Zeiss): diffuse retinal and RPE atrophy with pigment deposition. There is an island of healthy central retina, as well as several areas of healthy retina scattered throughout the periphery (A1, A2).

Green autofluorescence (Clarus 700, Zeiss): hypoautofluorescent areas corresponding to RPE atrophy predominate. The hyperautofluorescent areas correspond to healthy retina, including the central zones that include the fovea (B1, B2).

OCT (Cirrus 5000-HD, Zeiss): atrophy of RPE, choroid, and outer retina except in the foveal and parafoveal area (C1, C2). In the OCT of the right eye, external retinal tubulations secondary to outer retinal atrophy are observed (C1).

Description

11-year-old male patient comes for a check-up.

VA OD 20/20 OS 20/25.

The fundus examination shows severe chorioretinal atrophy both in the periphery and macula, with preservation of a central island of healthy retina (which explains the patient’s good vision) and several remnants of healthy retina scattered in the periphery. Autofluorescence allows for better differentiation between areas of healthy retina and areas of atrophy in the retina, RPE, and choroid. The suspected diagnosis of choroideremia was genetically confirmed.

Comments

Choroideremia is a dystrophy characterized by progressive development of atrophy of RPE, photoreceptors, and choriocapillaris. There is a diffuse pigment deposit, but not in the form of bone spicules as in RP, and waxy optic disc pallor does not appear. It usually debuts in the first decade of life and is caused by a mutation in the CHM gene. This gene is located on the X chromosome, making it an X-linked disease.

Description

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Indication