VDR and multiple sclerosis: Therefore, genetic variability in the VDR can have a great impact on the activity and function of vitamin D. The VDR gene is located at chromosome 12q13.11 and contains 11 exons and 4 polymorphic regions, namely, BsmI, ApaI, FokI, and TaqI. These single-nucleotide polymorphisms (SNPs) have been widely studied and are reported to be strongly associated with autoimmune diseases, such as asthma, multiple sclerosis, and type 1 diabetes.[1–4]