Three Single Nucleotide Polymorphisms of LOXL1’ in a Turkish Population with Pseudoexfoliation Syndrome and Pseudoexfoliation Glaucoma

OBJECTIVES: To investigate the three single nucleotide polymorphisms (SNPs) (rs3825942, rs1048661, and rs2165241) of the LOXL1 gene in pseudoexfoliation syndrome (XFS) and pseudoexfoliation glucoma (XFG) in the Turkish population. MATERIALS AND METHODS: DNA was obtained from blood samples of 48 XFS, 58 XFG, and 171 control subjects. Three LOXL1 SNPs (rs3825942, rs1048661, rs2165241) were investigated with real time PCR, a probe-based genotyping method, and melting curve analysis. RESULTS: All three SNPs of LOXL1 were significantly associated with XFS (rs3825942 p=3.54x10(-6), odds ratio [OR]=∞; rs1048661 p=0.008, OR=2.18; rs2165241 p=8.69x10(-9), OR=4.30) and XFG (rs3825942 p=3.41x10(-7), OR=∞; rs1048661 p=1.75x10(-5), OR=3.78; rs2165241 p=3.85x10(-11) OR=4.90). No significant differences were observed between the XFS and XFG groups for any of the SNPs. The GG genotype of rs3825942 was more valuable for distinguishing pseudoexfoliative cases from healthy individuals. The homozygous TT genotype of rs2165241 was associated with 6-fold increased XFS risk (p=8.15x10(-8), OR=6.32) and 7-fold increased XFG risk (p=1.45x10(-10) OR=7.95). The GGT haplotype consisting of all three risk alleles was associated with a 7.45-fold higher risk of XFS/XFG (p=8.65x10(-14), OR=7.45). Presence of T allele of rs2165241 conferred 3 times higher risk for men than women (p=6.78x10(-5), OR=3.202). CONCLUSION: LOXL1 SNPs are associated with increased risk for pseudoexfoliation in the Turkish population. T allele of rs2165241 was found to be the most important characterized risk factor for our cohort. All SNP distributions were similar to other European and American populations.