BBS is caused by 1 or more mutation(s) in any of at least 21 proteins related to the BBSome, which is a highly conserved complex comprising 8 core BBS proteins: BBS1, BBS2, BBS4, BBS5, BBS7, BBS8, BBS9, and BBS18/BBIP10 (16, 17). The gene discussed is BBS4; the disease is Bardet-Biedl syndrome.