Leber Congenital Amaurosis: Genotypes and Retinal Structure Phenotypes.

Leber congenital amaurosis (LCA) patients of 10 known genotypes (n = 24; age range, 3-25 years) were studied clinically and by optical coherence tomography (OCT). Comparisons were made between OCT results across the horizontal meridian (central 60(o)) of the patients. Three patterns were identified. First, there were LCA genotypes with unusual and readily identifiable patterns, such as near normal outer nuclear layer (ONL) across the central retina or severely dysplastic retina. Second, there were genotypes with well-formed foveal architecture but only residual central islands of normal or reduced ONL thickness. Third, some genotypes showed central ONL losses or dysmorphology suggesting early macular disease or foveal maldevelopment. Objective in vivo morphological features could complement other phenotypic characteristics and help guide genetic testing of LCA patients or at least permit a differential diagnosis of genotypes to be made in the clinic.