Typing of ARMS2 and CFH in age-related macular degeneration: case-control study and assessment of frequency in the Italian population.

OBJECTIVES

To determine the effects of the polymorphisms CFH Tyr402His and ARMS2 del443ins54 on susceptibility to age-related macular degeneration (AMD) and to find the frequencies of these single-nucleotide polymorphisms in an Italian population that was not examined clinically.

METHODS

A total of 286 control subjects (126 men and 160 women) and 159 white patients (73 men and 86 women) harboring exudative AMD in 1 eye were recruited. A third group of 182 DNA samples from blood donors of the same geographical areas were also typed to assess the frequency of CFH Tyr402His and ARMS2 del443ins54 polymorphisms in the general population. The data were analyzed statistically by a standard 2 x 2 table, Fisher exact tests, and odds ratios.

RESULTS

The deletion-insertion at chromosome 10q26 (del443ins54) showed the strongest association with AMD in terms of both P value and odds ratio (P = 2.7 x 10(-15); odds ratio = 3.25), and a highly significant association was also confirmed for Tyr402His at the CFH locus (P = 9.9 x 10(-13); odds ratio = 2.86). We found no differences in allele and genotype association between classic and occult choroidal neovascularization. We also observed that 39% of the samples in the general Italian population were at least 5.4 times more likely than control subjects to develop AMD.

CONCLUSIONS

To our knowledge, this is the first confirmation of the association of del443ins54 in Italian patients with AMD, and we also confirmed the association of Tyr402His with CFH. Genetic analysis of the general population suggested that analysis of the ARMS2 and CFH risk alleles alone may be helpful in differentiating high-risk individuals (odds ratio > 5.00) from low-risk individuals (odds ratio < 0.45).

CLINICAL RELEVANCE

Individuals at high risk for developing AMD could be identified and selected for specific prevention programs. In this context, the development of prevention programs based on dietary antioxidants or on close monitoring of at-risk individuals should be considered or suggested.