VDR and intervertebral disk degenerative disorder: Vitamin D receptor (VDR) gene is one of the most studied candidate genes associated with disc degeneration, which is located on chromosome 12q12–q14 with eight protein-coding and six untranslated exons.[5] Allelic variants of the gene encoding VDR, include TaqI (rs731236), FokI (rs2228570) and ApaI (rs7975232) have been reported to be associated with disc degeneration but still remains controversial.