CYP24A1 is responsible for the multiple side chain hydroxylation and/or oxidation in pathways leading to vitamin D inactivation in vivo.5 Numerous studies have investigated an association between CYP24A1 and autoimmune disease-T1DM, but with conflicting results.38,39 It has been shown that subclinical inflammation is also an important risk factor for GDM.20 In the present study, we found that the risk allele of rs2248359 was associated with increased leukocyte count, although it showed no association with GDM. This evidence concerns the gene CYP24A1 and gestational diabetes.