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Amar Shah, Lawrence J Singerman, Brent Zanke; Prevalence of CFH and ARMS2 Genetic Polymorphisms in African-American Patients with Age-Related Macular Degeneration. Invest. Ophthalmol. Vis. Sci. 2015;56(7 ):3786.
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It is well documented that non-Hispanic black persons have a significantly lower prevalence of age-related macular degeneration (AMD) as compared with Caucasians. This study explores differences in CFH and ARMS2, the two major susceptibility genes for AMD, genotypes as a potential explanation for this finding.
A multi-centered, population-based cross sectional study of 649 African American patients. Demographic information, smoking status, and AREDS stage (no signs AMD; early = category 1 and 2; intermediate = category 3; and advanced = category 4a/4b) was obtained for all participants. Genetic information collected included CFH polymorphisms at rs1048663, rs3766405, rs412852, rs11582939, and rs1066420, and ARMS2 genotype. When compared to known susceptibility or protective haplotypes, CFH haplotype was characterized as low, intermediate, or high risk. CFH haplotype risk was labeled unknown if previously unreported in the literature.
Of the 649 patients, 64 were excluded due to lack of indication of AMD status. The remaining distribution of patients (n=585) according to AMD status is shown in Figure 1. Across the entire cohort, only 27 patients (4.6%) had a high risk CFH haplotype. This is in comparison to 162 patients (27.7%) with a low risk CFH haplotype and 141 patients (24.1%) with an intermediate risk CFH haplotype. A significant proportion (43.6%), or 255 patients, had CFH haplotypes previously unreported in the literature. With further stratification, this percentage of unknown CFH haplotypes did not vary much across the four AMD status groups (Advanced - 40.6%; Intermediate - 44%; Eary - 43.6%; No signs - 43.8%). The prevalence of ARMS2 genotypes was 321 no ARMS2 risk alleles (54.8%), 212 single ARMS2 risk allele (36.2%), and 52 two ARMS2 risk alleles (8.9%).
To date, the genetics of black AMD patients has not been well described. Most AMD genetic research and treatment recommendations have been based off of Caucasian data. The considerable presence of previously unreported CFH haplotypes warrants further research to determine if they allow for further protection from progression to later AMD stages and contribute to the overall lower prevalence of AMD in African Americans. Additionally, continued exploration may aid in the pharmacogenomic selection of nutritional supplements based off of CFH and ARMS2 genotypes.
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