Fatme Al Anouti¹, Sarah El Hajj Chehadeh², Enas Osman², Gehad ElGhazali³, Habiba Al Safar^{2, 4,}

Despite the sunny weather in the Arabic Gulf Countries, vitamin D (VTD) insufficiency has been recently recognized as a serious health problem in this region. While diet and sun exposure are the main factors which determine the concentration of 25-hydroxyvitamin D₃ [25(OH)D₃], genetic variants VTD metabolizing enzymes, especially CYP2R1, CYP24A1 and CYP27B1, have gained a lot of interest lately. This study aims to investigate the association between VTD insufficiency and genetic variants of CYP2R1, CYP27B1 and CYP24A1 among young adult Emiratis. Healthy young adult United Arab Emirates (UAE) nationals (111 female, 52 male) with a mean age of 20.32 ± 2.35 years were recruited for the study. Genotyping for 5 single nucleotide polymorphisms (SNPs) in CYP2R1, CYP24A1 and CYP27B1 genes were performed by TaqMan^® assays, while serum 25(OH)D₃ was measured by Diasorin analyzer (LIAISON). Our results showed that the GT+TT genotype of CYP27B1 (rs10877012) (OR: 6.13, 95%CI [1.76-21.33], p=0.001) and the AG+GG genotype of CYP27B1 (rs4646536) (OR: 2.57, 95%CI [1.02-6.49], p=0.040) were significantly more frequent in VTD insufficient subjects while the GG genotype of CYP24A1 (rs2762939) (OR: 0.10, 95%CI [0.006-1.81], p=0.036) and the TT genotype of CYP24A1 (rs6013897) (OR: 0.10, 95%CI [0.006-1.76], p=0.033) were significantly more frequent in sufficient subjects. Moreover, the haplotype (GTGA) was significantly more frequent in sufficient subjects (p=1.22x10^-5), while the frequency of haplotype GTTG was significantly high in the insufficient group (p=0.004). The data strongly suggest that genetic variants relevant to VTD metabolism could play an important role in defining VTD status among the young adult Emirati population.

Vitamin D metabolism, CYP2R1, CYP24A1 and CYP27B1 Genetic variants, Emiratis