Purpose: To investigate the association between complement factor H (CFH) and C-reactive protein (CRP) genotypes and response to photodynamic therapy (PDT) treatment for neovascular age-related macular degeneration (AMD).
Design: Retrospective cohort study.
Participants: The study cohort consisted of 273 neovascular AMD patients treated with PDT.
Methods: Genotypes were determined for the common T-->C single nucleotide polymorphism (SNP) in exon 9 of the CFH gene (rs1061170; Y402H), as well as 9 selected tagging SNPs across the CRP gene (rs2808635, rs1417938, rs1800947, rs1130864, rs1205, rs3093077, rs876538, rs876537, and rs1572970). Visual acuity outcome after PDT was retrospectively calculated and patients were classified as PDT-positive responders or PDT-negative responders. Logistic regression analysis was used to evaluate the association between individual SNPs and PDT treatment response while adjusting for relevant covariates.
Main outcome measures: Response to PDT treatment defined by visual acuity; genotypes of CFH Y402H and CRP polymorphism.
Results: Of the 273 patients, 75 had a positive response after PDT treatment. The frequency of CC genotype of the CFH Y402H polymorphism in the PDT-positive response group was lower than in the negative PDT response group (26.4% vs 31.6%) but this difference failed to reach statistical significance. Two CRP SNPs (rs2808635 and rs876538) were significantly associated with PDT treatment response. Positive treatment response was seen in individuals homozygous for the minor allele of the rs2808635 (GG; odds ratio [OR], 3.92; 95% confidence interval [CI], 1.40-10.97; P = 0.048) and rs876538 (AA; OR, 6.49; 95% CI, 1.65-25.47; P = 0.048) variants after adjusting for relevant covariates. The remaining 7 CRP genetic variants did not reveal any significant association with treatment response.
Conclusions: Our data did not show significant association between the CFH Y402H polymorphism and PDT treatment response for neovascular AMD; however, CRP genetic variants were associated with a positive response to PDT treatment for neovascular AMD.