Studies has shown that in some families, even when the father, sons and brothers carried the same variant, only some of them presented with CBAVD, suggesting that a second unidentified mutations may lie in noncoding regions of the gene in CBAVD patients26,27, or that CFTR gene variant may not be the absolute influencing factor for the occurrence and development of CBAVD, and some other mechanisms and environmental factors might also be involved. Here, CFTR is linked to congenital bilateral aplasia of vas deferens from CFTR mutation.