Bu et al reported that single nucleotide polymorphism (SNP) in CYP2R1 was associated with 25(OH)D concentration in Caucasian.5 Significant associations between SNPs in CYP27B1 and 25(OH)D concentration were observed by Orton.6 However, whether there are transmission disequilibriums for these genetic variants in vitamin D deficiency families remains unclear. Here, CYP2R1 is linked to vitamin D deficiency.