Association of sequence variation in the CX3CR1 gene with geographic atrophy age-related macular degeneration in a Greek population

Abstract

Purpose: To explore the association of two single nucleotide polymorphisms (SNPs) in the CX3CR1 gene with grades of age-related macular degeneration (AMD) in a population-based setting.

Methods: The Thessaloniki Eye study is a cross-sectional population-based epidemiologic study of chronic eye diseases in Thessaloniki, Greece. A total of 371 subjects were included and classified according to their AMD status. Subjects with AMD Grades 0-1 (n = 188) were compared to those with AMD Grades 2-3 (n = 138), to those with AMD Grade 4 (geographic atrophy) (n = 20) and to those with AMD Grade 5 (neovascular AMD) (n = 25) with regard to the presence of CX3CR1 polymorphisms (V249I and T280M). Polychotomous logistic regression analysis adjusted for age, gender, and smoking was conducted and the log-additive allelic model was preferred.

Results: Participants with AMD Grade 4 were approximately three times more likely to carry the VI249 and nine times more likely to carry the II249 alleles, compared to those with AMD Grades 0-1, whereas those with AMD Grades 2-3 or Grade 5 did not differ. The T280M polymorphism was not associated with either AMD Grades 2-3 or AMD Grades 4 or 5.

Conclusion: In this Greek population, after adjusting for known risk factors, increased risk of geographic atrophy (GA) AMD among the carriers of the V249I polymorphism in the CX3CR1 gene was found. Our study failed to reveal any association with the T280M polymorphism reported in previous studies. Additional studies in different ethnic populations using standardized methodology are needed in order to confirm this association.