CYP27A1 and congenital bilateral aplasia of vas deferens from CFTR mutation: In addition, the expression of vitamin D metabolism genes, such as CYP27A1 and CYP2R1, was downregulated in the valve samples of patients with CAVD, as was the expression of vitamin D response genes, including VDR, FGFR1, and FGFR2 (Figure 7B).