Evaluation of LOXL1 polymorphisms in exfoliation syndrome in a Chinese population

PURPOSE To evaluate the association profiles of the lysyl oxidase-like 1 (LOXL1) gene polymorphisms with exfoliation syndrome in a Chinese population. METHODS Fifty unrelated patients with exfoliation syndrome and 125 control subjects were included. Genotypes of the three single nucleotide polymorphisms (SNPs) of LOXL1 (rs1048661, rs3825942, and rs2165241) were analyzed by direct sequencing, and a case-control association study was performed. RESULTS The three SNPs were significantly associated with exfoliation syndrome (XFS) and exfoliation glaucoma (XFG) individually. After controlling for rs3825942 and rs2165241, the association between rs1048661 and XFS/XFG remained significant (p=3.6 x 10(-7)). At this SNP, the T allele and TT genotype conferred a 7.59-(95% confidence interval [CI]: 3.87-14.89, p=6.95 x 10(-11)) and 8.69-(95% CI: 4.15-18.20, p<1.00 x 10(-7)) fold increased risk to the disease. The alleles of T at rs1048661 and C at rs2165241 were found to be risk alleles in Chinese subjects, which were opposite to Caucasian individuals. The haplotypes T-G, defined by SNPs rs1048661 and rs3825942, and T-C by SNPs rs1048661 and rs2165241, were also significantly associated with the disorder. However when the genotypic or allelic frequencies of the three SNPs were compared between XFS and XFG, no significant difference was detected. CONCLUSIONS LOXL1 is a susceptibility gene of XFS/XFG in the Chinese population, and the association is mainly attributed to SNP rs1048661. The risk alleles of rs1048661 and rs2165241 in Chinese subjects were found to be opposite to that of Caucasians. The genotypic and allelic distributions of these SNPs are similar between XFS and XFG.