Examples of such congenital disorders and the affected enzymes include Smith-Lemli-Opitz syndrome (SLOS; DHCR7, OMIM# 270400), desmosterolosis (DHCR24, OMIM# 602398), lathosterolosis (sterol-C5-desaturase, OMIM# 607330), and mevalonate kinase (MVK, OMIM# 251170) deficiency (see Fig. 2) (19). The gene discussed is DHCR7; the disease is Smith-Lemli-Opitz syndrome.