HEREDITARY CHOROIDAL DYSTROPHIES 1. Choroideremia 2. Gyrate atrophy 3. Central areolar choroidal dystrop 4. Diffuse choroidal atrophy
HEREDITARY CHOROIDAL DYSTROPHIES
1. Choroideremia
2. Gyrate atrophy
3. Central areolar choroidal dystrophy
4. Diffuse choroidal atrophy
ChoroideremiaInheritance - X-linked recessive
• Circumscribed atrophy of RPE and choroid• Starting in periphery
• Gradual central spread• Fovea spared until late
Presents - first decade with nyctalopiaPrognosis - good VA until lateERG - reduced
Progression
FA in choroideremia
• Preservation of larger choroidal vessels• Hypofluorescence at fovea due to preservation of RPE• Surrounding irregular hyperfluorescence due to preservation of choriocapillaris and partial loss of RPE
• Normal retinal vasculature• Diffuse loss of choriocapillaris
Female carriers of choroideremia
Peripheral diffuse pigmentary granularity
Central patchy atrophy and mottling of RPE
Gyrate atrophy
• Mid-peripheral, circular patches of chorioretinal atrophy
• Enlargement and confluence
• Central and peripheral spread• Late retinal vascular attenuation
Inheritance - autosomal recessivePresents - first decade with axial myopia and nyctalopiaPrognosis - usually good VA until lateERG - severely reduced
Cause - deficiency of ornithine keto-acid aminotransferase
• Fovea spared until late
Progression
Central areolar choroidal dystrophy
• Bilateral, circumscribed, atrophic maculopathy• Prominent large choroidal vessels
Inheritance - dominantPresents - fifth decadePrognosis - poorERG - normal
Diffuse choroidal atrophy
• Diffuse atrophy of RPE and choriocapillaris• Prominent large choroidal vessels
Inheritance - dominantPresents - fourth to fifth decadesPrognosis - poorERG - reduced