Association of Toll-like receptor 4 gene polymorphisms in Japanese subjects with primary open-angle, normal-tension, and exfoliation glaucoma

Abstract

Purpose: To determine whether polymorphisms in the Toll-like receptor 4 (TLR4) gene are associated with primary open-angle glaucoma (POAG), normal-tension glaucoma (NTG), and exfoliation glaucoma (XFG) in Japanese individuals.

Design: Genetic association study.

Setting: Multicenter study.

Study population: One hundred eighty-four unrelated Japanese patients with POAG, 365 unrelated patients with NTG, and 109 unrelated patients with XFG from 5 hospitals.

Procedures: Genomic DNA was extracted from leukocytes of the peripheral blood, and 8 polymorphisms in the TLR4 genes were amplified by polymerase chain reaction (PCR) and directly sequenced. Allele and genotype frequencies and the inferred haplotypes were estimated.

Main outcome measures: Differences in allele and genotype frequencies and haplotypes between subjects with POAG, NTG, and XFG.

Results: The allele frequency of rs2149356 of the TLR4 gene in the POAG, NTG, and XFG groups was the most significantly different from that of the control group (minor allele frequency 0.446, 0.395, 0.404, vs 0.308; P = .000058, P = .0030, and P = .015). The allele frequencies of the 5 TLR4 SNPs were higher in all of the glaucoma groups than that in the control group. The statistics of genotypes of TLR4 were approximately the same for all allele frequencies. The haplotypic frequencies with Tag SNPs studied earlier showed that only POAG was statistically significant. Other haplotypes, such as rs10759930, rs1927914, rs1927911, and rs2149356, had higher statistical significance (overall P = .00078 in POAG, overall P = .018 in NTG, and overall P = .014 in XFG).

Conclusions: This study demonstrated that TLR4 polymorphisms are associated with NTG in the Japanese, and they also play a role in the pathogenesis of POAG and XFG.