Genetic Polymorphisms and the Phenotypic Characterization of Individuals with Early Age-Related Macular Degeneration.

PURPOSE: While the importance of risk polymorphisms for the pathogenesis of age-related macular degeneration (AMD) is well established, their impact on morphological and functional phenotypes is largely unclear. We aimed to characterize individual phenotypes in patients who were either homozygous for a risk allele in the CFH gene, ARMS2 gene, or both as compared to non-carriers.

METHODS: Patients with early AMD (n = 85) were assessed during a follow-up examination of a prospective study (MARS) with multimodal diagnostics including SD-OCT and microperimetry.

RESULTS: Compared to non-carriers, OCT scans revealed lower retinal thickness in patients homozygous for CFH or ARMS2, which was caused by a significantly reduced photoreceptor layer. The number and ultrastructure of drusen were also significantly different.

CONCLUSIONS: These findings indicate that patients with risk alleles demonstrate distinct phenotypic differences of morphology and function as compared to non-carriers. In particular in the CFH group, a loss of photoreceptors occurred concomitantly with reduced retinal sensitivity. Further studies might help to better understand the pathophysiology.