Lack of association of SNP rs4236601 near CAV1 and CAV2 with POAG in a Saudi cohort

PURPOSE: To determine the role of the recently discovered primary open angle glaucoma (POAG) single nucleotide polymorphism (SNP) rs4236601 near the caveolin-1 (CAV1) and CAV2 among patients and controls from Saudi Arabia. METHODS: A cohort of 220 POAG patients and 405 control subjects from Saudi Arabia were genotyped for a SNP (rs4236601;g.2891 G>A) in the chromosome 7q31 locus near CAV1 and CAV2 using a standard polymerase chain reaction (PCR) and sequencing method. RESULTS: The minor allele frequency (MAF) of rs4236601 was 0.3 in controls and 0.31 in POAG patients. We detected no statistical difference when we compared the allele frequencies between POAG patients and control subjects (p=0.699). Similarly, we detected no statistical difference in the frequency of the three possible rs4236601 genotypes between patients and controls. The p-values were 0.928 and 0.683 for heterozygous genotype (G/A) and homozygous mutant genotype (A/A), respectively. We found no statistically significant difference among patients with any of the three possible genotypes and various clinical indices important for glaucoma. Among patients with homozygous (A/A), the mean IOP was higher (21.4) compared to patients with G/G wildtype (20.4) and to patients with G/A genotype (18.5). However, this apparent difference did not reach the statistical significance threshold (p=0.062). CONCLUSIONS: We were unable to detect this association in our POAG-patients from Saudi Arabia, suggesting that this risk factor may not have a strong effect in all populations. A founder effect may play a role in certain populations where the link was established.