Association of LOXL1 gene polymorphisms with exfoliation syndrome/glaucoma and primary open angle glaucoma in a Turkish population

PURPOSE To investigate the association of lysyl oxidase like 1 (LOXL1) variants with exfoliation syndrome (XFS), exfoliation glaucoma (XFG), and primary open angle glaucoma (POAG) in a Turkish population. METHODS Two LOXL1 single nucleotide polymorphisms (SNPs), rs1048661 (R141L) and rs3825942 (G153D), were analyzed in 300 Turkish patients (100 patients with XFS, 100 patients with XFG, 100 patients with POAG) and 100 control subjects. RESULTS The T allele of rs1048661 was underrepresented in patients with XFS (odds ratio [OR]=0.334, 95% confidence interval [CI]: 0.198-0.564, p=2.54 × 10(-5)) and XFG (OR=0.366, 95% CI: 0.219-0.611, p=8.56 × 10(-5)) compared to the control subjects. None of the patients with XFS or XFG had the A allele of rs3825942, whereas 16% of the control subjects had that variant (OR=0.025, 95% CI: 0.003-0.188, p=3.69×10(-9)). No association was observed between the SNPs studied and POAG. By using logistic regression analysis, the effect of rs1048661 remained significant (p=8.45 × 10(-8)) after controlling for the effect of rs3825942, whereas rs3825942 was not significant with conditioning on rs1048661. Female gender was protective against the disease controlling with the effect of the two SNPs (OR=0.527, 95% CI: 0.358-0.776, p=0.001). CONCLUSIONS The findings of the current study indicate that in a logistic regression analysis model the T allele of rs1048661 is the most important risk-modifying factor for the development of XFS and XFG. Our results also confirm in a Turkish population the findings of previous reports describing the association between LOXL1 polymorphisms and XFS/XFG but not with POAG. The allele and genotype distribution in this cohort appear to be similar to those of Caucasians.