Purpose: A recent study identified single nucleotide polymorphisms (SNPs) within the IL-1 gene cluster at chromosomal locus 2q13 that were associated with reduced risk for primary open-angle glaucoma (POAG) in whites. The purpose of this study was to investigate the association between IL-1 SNPs and glaucoma in Chinese patients with either POAG or primary-angle closure glaucoma (PACG).
Methods: Patients with POAG with a mean IOP without treatment that was consistently <21 mm Hg on diurnal testing were classified as having normal-tension glaucoma (NTG) and those with higher IOP were classified as having high-tension glaucoma (HTG). Subjects with PACG had at least 180 degrees of angle closure on gonioscopy. Genotypes were determined by polymerase chain reaction and restriction digest enzymes at the following loci: IL1A (-889C/T), IL1B (+3953C/T), and IL1B (-511C/T). The association of individual SNPs with glaucoma was evaluated by using chi(2) testing. Haplotype analysis was performed with the PHASE program, with haplotype frequency estimated for combined cases and controls, assuming Hardy-Weinberg equilibrium (HWE) of haplotypes.
Results: Of the Chinese subjects studies, 194 had POAG (94 NTG and 100 HTG), 125 had PACG, and 79 were normal control subjects. There was no significant difference in IL-1 SNP or allele frequencies for in subjects with POAG or PACG compared with control subjects, or between NTG and HTG. None of the common haplotypes showed any significant difference between the HTG, NTG, PACG, and normal control subjects.
Conclusions: This study did not find an association between IL-1 gene cluster polymorphisms and glaucoma in this sample of Chinese subjects.