GJB2 and cystic fibrosis: Generally, we could divide the common AR and X-linked conditions into 4 groups to discuss: the group of hearing impairment contained GJB2 and USH2A; the group of genetic anemia including HBB and G6PD genes; the group of cystic fibrosis (CFTR); the group of metabolism disorders coded by ATP7B and GAA gene.