The active form of vitamin D (calcitriol) is a pleiotropic hormone exerting important biological functions, mainly as a key factor in the regulation of correct calcium and bone metabolism. Two hydroxylases are responsible for vitamin D (cholecalciferol) hydroxylation at positions 1 and 25 of the molecule, namely 1-alpha-hydroxylase and 25-hydroxylase, encoded by the genes CYP27B1 and CYP2R1, respectively. Polymorphic variants in these genes are recognized to influence individual vitamin D status.
Here, we looked for associations between five polymorphic variants, three in CYP2R1 and two in CYP27B1, and serum levels of 25-hydroxy-vitamin D [25(OH)D3] in an Italian adult population.
The AA genotype, homozygous for the minor allele of the single nucleotide polymorphism (SNP) rs10741657 in CYP2R1, was significantly associated with higher mean levels of 25(OH)D3 in the blood, in accordance with results previously found in other populations.
Our data, confirmed that the AA genotype is a favorable genetic status in reducing individual risk of vitamin D deficiency and insufficiency, and that GG-bearing individuals may benefit more from supplementation with calcifediol rather than cholecalciferol.
