Determinants of vitamin D status: focus on genetic variations

Purpose of review The role of vitamin D beyond its importance for bone health is under much debate. In this article, we review recent evidence for genetic influences on 25-hydroxyvitamin D [25(OH)D] and discuss the uses of this information and its importance for public health. Recent findings Findings from large-scale genome-wide association meta-analyses on 25(OH)D confirmed the associations for loci nearby genes encoding vitamin D binding protein (GC, group component), 7-dehydrochlesterol reductase (DHCR7), 25-hydroxylase (CYP2R1) and 24-hydroxylase (CYP24A1), all influencing key sites for vitamin D metabolism. Findings from candidate gene studies have been inconsistent, with some implicating an association with 25(OH)D for loci near the gene encoding the hormonal vitamin D activation enzyme (CYP27B1). Summary The amount of variation in 25(OH)D explained by genetic determinants is small compared with environmental exposures. Information on genetic variants affecting 25(OH)D can be used as tools for Mendelian randomization analyses on vitamin D, and they provide some potential for the use as drug targets.