CFTR and cystic fibrosis: The c.428delG mutation is annotated in dbSNP (rs534542684), and its MAF in the general population is surprisingly high (0.39%, 378 out of 96,534 alleles in the ExAC db), reminiscent of the most common deafness (c.35delG in GJB2; 0.60% in the ExAC database) or cystic fibrosis (p.Phe508del in CFTR; 0.67% in the ExAC database) mutation.