Lack of Association Between Polymorphisms in TXNRD2 and LMX1B and Primary Open-Angle Glaucoma in a Saudi Cohort

Abstract

Objective: Recent studies have demonstrated an association of single nucleotide polymorphisms (SNPs) rs35934224 in TXNRD2 and rs6478746 near LMX1B genes in primary open-angle glaucoma (POAG) among Europeans. We performed a retrospective, case-control study to investigate the association between the rs35934224 (TXNRD2) and rs6478746 (LMX1B) and POAG in a middle-eastern population from Saudi Arabia.Methods: DNA from 399 participants consisting of 150 POAG cases (83 males and 67 females) and 249 controls (135 males and 114 females) were genotyped using TaqMan® real-time PCR. Statistical tests were performed to evaluate genetic association with POAG and related clinical indices.Results: The minor allele frequency (MAF) of rs35934224[T] was 0.19 and 0.20 in POAG and controls, respectively. The difference was non-significant (odds ratio [OR] = 1.08, 95% confidence interval [CI] = 0.75–1.55, p = 0.663). Likewise, rs6478746[G] MAF was 0.12 in both cases and controls with no statistical significance (OR = 1.02, 95% CI = 0.67–1.56, p = 0.910). Genotype analysis showed no association with POAG for both the SNPs in combined and gender-stratified groups. Regression analysis showed no significant effect of risk factors such as age, sex, rs35934224, and rs6478746 genotypes on POAG outcome. Furthermore, both the SNPs showed no significant genotype effect on clinical indices such as intraocular pressure (IOP) and cup/disc ratio in POAG patients.Conclusions: Rs35934224 in TXNRD2 and rs6478746 near LMX1B genes are not associated with POAG or related clinical indices such as IOP and cup/disc ratio in a Saudi cohort. Since the study is limited by sample size further investigations are needed to confirm these results in a larger cohort.

Lack of Association of Polymorphism Located Upstream of ABCA1 (rs2472493), in FNDC3B (rs7636836), and Near ANKRD55–MAP3K1 Genes (rs61275591) in Primary Open-Angle Glaucoma Patients of Saudi Origin

“…A retrospective case-control study was performed. POAG patients and controls were recruited at King Abdulaziz University Hospital, Riyadh, Saudi Arabia as described in detail elsewhere [ 20 ]. Briefly, POAG patients showed the presence of (1) glaucomatous changes at the optic disk or retinal nerve fiber changes (such as narrowing or absence of neuroretinal rim, cup-to-disc ratio exceeding 0.7, an inter-eye asymmetry of >0.2, and/or notching); (2) corresponding visual field defects typical of glaucoma; (3) bilaterally open angles; (4) late-onset; (5) high IOP (≥21 mm Hg) in one or both eyes before treatment; (6) and no secondary causes of glaucomatous optic neuropathy with identifiable causes such as exfoliative glaucoma, angle-closure, pigmentary glaucoma, post-traumatic, infectious or inflammatory glaucoma (e.g., uveitis), or post-surgical and post-medication glaucoma (e.g., after corticosteroids).…”

Molecular genetics of primary open-angle glaucoma

“…[ 69 , 169 ] Various population-specific study reports showed a link between POAG and TXNRD2 SNPs, including African,[ 72 ] European,[ 166 ] and Brazilian populations,[ 170 ] whereas no such association was found in a study performed on a Saudi cohort. [ 171 ]…”