BBS9 and Bardet-Biedl syndrome: Two members of the Bardet-Biedel Syndrome (BBS) gene family, which is involved in ciliogenesis, have de novo missense variants in CDD probands: BBS5 and BBS9. Although the specific protein-changing variants identified in CDD subjects were rare and not previously associated with disease, we reviewed the literature and found some overlap between CDD candidate genes and genes potentially associated with other neurological disorders (Table 2).