SNP rs2157719 in the CDKN2B-AS1 gene gene may influence cup-to-disc ratio in patients with primary open angle glaucoma

Background: Several studies have provided strong evidence that gene variants at the cyclin-dependent kinase inhibitor 2B antisense non-coding RNA (CDKN2BAS1) locus of 9p21 is an important risk factor in the development of primary open angle glaucoma (POAG) making it a strong candidate for risk factor screening. Objectives: The present study investigated the possible association of SNP rs2157719 in CDKN2B-AS1 with POAG and specific glaucoma indices used to assess disease severity in a Saudi cohort. Materials and methods: Genotyping of SNP rs2157719 was performed in 85 unrelated POAG cases and 95 normal controls of Saudi origin using Taq-Man® realtime PCR assay and its association with the POAG and other clinical indices was evaluated. Results: The genotype frequencies did not deviate significantly from the Hardy-Weinberg equilibrium (p>0.05). The minor ‘G’ allele frequency was observed to be 0.18 in cases and 0.21 in controls. Both the genotype and allele frequencies did not vary significantly between cases and controls. However, the homozygous mutant genotype (G/G) was found to be significantly associated with family history of glaucoma (p= 0.018), smoking (p= 0.033) and awareness of glaucoma (p= 0.039). In addition, carriers of the heterozygous (A/G) genotype had significantly higher cup/disc ratio (p= 0.028) as compared to the wild-type. Conclusion: SNP rs2157719 in the CDKN2B-AS1 is not associated with POAG but may affect cup-to-disc ratio and thereby modulate optic nerve pathology.