Complement Factor H Y402h and Age-Related Macular Degeneration (amd) in India: Results From the Indeye Study

Abstract

Purpose: : Information is limited on the association between Y402H variant and AMD in most ethnicities apart from European populations. We therefore present results from an analysis of the Indeye dataset.

Methods: : 4772 participants aged 60 and above from the two centres (North and South India) gave consent to blood collection, genotyping and had fundus photography. AMD status of 1276, (27%) was unassignable owing to cataract. Of the remainder, early AMD Stage 1 (soft distinct drusen or pigmentary irregularities) was graded in 28%, stage 2 in 4.9% (soft indistinct (≥125µm) or reticular drusen only or Soft distinct drusen (≥ 63µm) with pigmentary irregularities), and late AMD in 0.8% (n=40). 1862 had no signs of early or late AMD (AMD 0). Genotyping was carried out using RT-PCR. Multinomial logistic regression was used to determine the association between early AMD (stages 1 or 2 ), late AMD and Y402H compared with AMD 0, adjusted for age, sex, socioeconomic status, tobacco smoking and diabetes status and clustering by village.

Results: : Overall the genotype frequencies of Y402H were 48%, 42% and 10% for the common homozygote (TT), heterozygote (CT) and rare homozygote (CC), respectively, and were in Hardy-Weinberg equilibrium. For early AMD Stage 1 the relative risk ratios, 95% confidence intervals and p for trend were 0.86 (0.75-1.00) and 0.95 (0.74-1.22) p=0.3 for CT and CC genotypes versus TT, respectively, for early AMD stage 2 , 0.89 (0.70-1.14) and 0.78 (0.48-1.25) p=0.3 respectively, and for late AMD 1.70 (0.79-3.62) and 2.35 (0.81-6.76) p=0.07. Genotype frequencies were similar in controls and those with ungradable images.

Conclusions: : We found no evidence for an association between the Y402H risk genotype and early AMD. For late AMD our results are similar results to those in European populations but are not conclusive due to the small number of late AMD cases.

Keywords: age-related macular degeneration • genetics • clinical (human) or epidemiologic studies: biostatistics/epidemiology methodology