PURPOSE: Several dietary factors have been associated with glaucoma. Among them, dietary antioxidant intake (i.e., Vitamin C and vitamin A) in association with glaucoma has been analyzed, but with mixed results. Genetic factors may play a role in modulating the effect of dietary antioxidant intake on glaucoma; however, nutrigenetic studies in this field are scarce. Our aim was to study the association between selected polymorphisms in key proteins related to Vitamin C and Vitamin A concentrations and primary open-angle glaucoma (POAG). METHODS: We performed a case-control study matched for age, sex, and bodyweight. We recruited 300 subjects (150 POAG cases and 150 controls) from a Mediterranean population and determined the plasma concentrations of Vitamin C and Vitamin A for each subject. We selected the following single-nucleotide polymorphisms (SNPs) in genes related to Vitamin A and Vitamin C concentrations: rs176990 and rs190910 in the retinol-binding protein 1 (RBP1) gene; and rs10063949 and rs1279683 in the Na?-dependent L-ascorbic acid transporters 1 and 2, respectively (encoded by the SLC23A1 and SLC23A2 genes). RESULTS: We found a statistically significant association between the rs1279386 (A>G) SNP in SLC23A2 and POAG risk. In the crude analysis, homozygous subjects for the G allele (GG subjects) had higher risk of POAG than other genotypes (OR: 1.67; 95% CI: 1.03-2.71). This association remained statistically significant (p=0.010) after multivariate adjustment for potential confounders. We also found that POAG patients had lower plasma Vitamin C concentrations than control subjects (9.9?1.7 ?g/ml versus 11.7?1.8 ?g/ml, p<0.001). Moreover, we consistently detected a significant association between the rs1279386 SNP in SLC23A2 and plasma Vitamin C concentrations: GG subjects had significantly lower plasma Vitamin C concentrations than the other genotypes (9.0?1.4 ?g/ml versus 10.5?1.6 ?g/ml, p<0.001 in POAG cases and 10.9?1.6 ?g/ml versus 12.1?1.8 ?g/ml, p<0.001 in controls). The rs10063949 SNP in SLC23A1 was not associated with either plasma Vitamin C concentrations or POAG risk. Similarly, SNPs in RBP1 were not associated with Vitamin A concentrations or POAG risk. CONCLUSIONS: The rs1279683 SNP in SLC23A2 was significantly associated with lower plasma concentrations of Vitamin C and with higher risk of POAG in GG subjects.
Share or Bookmark this page: You will need to have an account with the selected service in order to post links or bookmark this page.