Evaluation of Genetic Polymorphisms in Clusterin and Tumor Necrosis Factor-Alpha Genes in South Indian Individuals with Pseudoexfoliation Syndrome

Abstract

Purpose: The aim of this study was to explore the potential association of genetic variants across clusterin (CLU) and tumor necrosis factor-alpha (TNF-α) genes in South Indian individuals with pseudoexfoliation syndrome (PEXS) and pseudoexfoliation glaucoma (PEXG).Materials and Methods: A total of 523 individuals including 299 unrelated cases (150 PEXS and 149 PEXG) and 224 age- and ethnically-matched healthy controls were recruited for genetic analysis. Six single-nucleotide polymorphisms (SNPs) including, five CLU SNPs (rs11136000, rs2279590, rs9331888, rs9331931, rs3087554) and one promoter SNP (rs1800629) of TNF-α were genotyped in all study subjects. Genotyping of CLU SNPs were performed using the TaqMan allelic discrimination assay while TNF-α SNP was genotyped using polymerase chain reaction (PCR)-based restriction fragment length polymorphism (RFLP) analysis. Association analysis was performed by determining the distributions of genotype and allele frequencies, Hardy–Weinberg equilibrium, and chi-square p values and odds ratios as implemented in the Golden Helix SNP & Variation Suite (SVS).Results: Five CLU SNPs did not show any significant differences in allele frequencies between patients and control subjects (rs3087554, p = 0.919, OR = 1.01, 95% CI: 0.77–1.33; rs2279590, p = 0.432, OR = 1.12, 95% CI: 0.84–1.51; rs9331931, p = 0.310, OR = 1.24, 95% CI: 0.81–1.89; rs11136000, p = 0.072, OR = 1.31, 95% CI: 0.97–1.76; rs9331888, p = 0.911, OR = 1.01, 95% CI: 0.78–1.31). The investigation of TNF-α SNP established a significant association with PEXS and PEXG (p = 0.042, OR = 0.61, 95% CI: 0.38–0.99). However, this association did not remain significant after Bonferroni correction.Conclusions: Our data suggest that genetic variants in CLU and TNF-α genes do not play a major role in the development of PEXS and PEXG in the South Indian population.