Abstract
Background: To Investigate whether the g.4760C>T polymorphism in the promoter region of the catalase gene (CAT) is a risk factor for primary angle closure glaucoma (PACG) in the Saudi population.
Methods: 138 unrelated PACG patients and 403 unrelated control subjects from Saudi Arabia were genotyped for a single nucleotide polymorphism (SNP; rs1001179; g.4760C>T) utilizing Taq-Man (R) assay. The association between different genotypes and various clinical indices important for PACG was also investigated.
Results: The distribution of different genotypes was comparable between both study groups. The genotype "C/C" was predominant among cafses; 94 (68.1%) and controls; 289 (71.7%). Heterozygous genotype "C/T", was present in 41 (29.7%) of cases and 103 (25.6%) of controls, where the homozygous variant genotype was present in only 3 (2.2%) of cases and 11 (2.7%) of the controls. The distribution of variant allele was similar in both study groups (p= 0.568). Interestingly, there was a trend of association between the type of the variant (homozygous variant, heterozygous and wildtype genotype) and one important parameter for PACG, which is visual acuity. The visual acuity increase was; 0.62 (+/- 0.74), 0.88 (+/- 0.88) and 1.27 (+/- 0.95) in patients carrying the "C/C", "C/T" and "T/T" genotypes respectively, which was statistically significant in both ANOVA and pairwise individual T tests (p = 0.022, 0.031 and 0.039) when compared to controls.
Conclusions: This variant is possibly associated with visual acuity in PACG patients and thus had the potential to be used as a parameter for assessing PACG severity.