Interestingly, circ-CCND1, whose expression is upregulated in CAVD samples, was shown to promote osteogenic transition of VICs by sponging miR-138-5p, thereby activating the osteogenic CCND1/P53/P21 pathway (48). The gene discussed is CCND1; the disease is congenital bilateral aplasia of vas deferens from CFTR mutation.