OMIM:04896 gene; 209900 phenotype; 236700 phenotype; BBS6 605231; McKusick-Kaufman syndrome; MKKS hydrometrocolpos syndrome; hydrometrocolpos, postaxial polydactyly, and congenital heart malformation; HMCS Kaufman-Mckusick syndrome. Y37C (604896.0003), T57A (604896.0010), and C499S (604896.0013): increased MKKS degradation and reduced solubility relative to wildtype MKKS, and the mutant H84Y (604896.0001). R155L, A242S, and G345E mutations: increased MKKS degradation only. The gene discussed is MKKS; the disease is congenital heart malformation.