The Role of SNPs in IL1RL1 and IL1RAP Genes in Age-related Macular Degeneration Development and Treatment Efficacy

Background: Age-related macular degeneration (AMD) affects the central part of the retina and causes blindness. In developed countries, AMD occurs in people over 50 years old. Important factors for AMD pathogenesis are an immune response, inflammation, and genetic factors. This study aimed to determine the impact of IL1RL1 rs1041973 and IL1RAP rs4624606 single nucleotide polymorphisms (SNPs) on the occurrence of AMD and the outcome of treatment with aflibercept and bevacizumab. Patients and Methods: 563 patients with AMD and 281 healthy candidates were evaluated. Patients with exudative AMD were treated with intravitreal bevacizumab and aflibercept and, after 6 months based on the changes in bestcorrected visual acuity and central macular thickness, were classified as 'responders' or 'poor-responders'. Genotyping of IL1RL1 rs1041973 and IL1RAP rs4624606 was accomplished using real-time PCR. Age was compared using the Mann-Whitney U-test. Categorical data (gender, genotype, and allele distributions) compared between groups using the x2 test or the Fisher's exact test. Associations of gene polymorphisms were calculated using logistic regression analysis with adjustment for age in exudative and atrophic AMD analysis. An adjusted significance threshold for multiple comparisons a=0.025 was applied. Results: Statistically significant differences in the distribution of IL1RAP rs4624606 genotypes (TT, TA and AA) were found between males with atrophic AMD and controls: 50%, 42.9% and 7.1% vs. 69.7%, 30.3% and 0%, respectively, p=0.015. Moreover, we found that 'responders' had a significantly better best-corrected visual acuity than 'poor-responders' before treatment (p=0.032). The central macular thickness was significantly lower in exudative AMD patients with IL1RL1 rs1041973 AA genotype than in wild type and heterozygous (CC+CA) genotype carriers before treatment (p=0.017). Conclusion: IL1RAP rs4624606 may be associated with atrophic AMD in males while IL1RL1 rs1041973 may play a protective role against macular thickening in exudative AMD patients.