SC5D and lathosterolosis: Mutations in Dhcr7 and Sc5d, which encode enzymes that catalyze the terminal steps in cholesterol biosynthesis, impair HH signaling in target cells and cause the congenital malformation syndromes Smith-Lemli-Opitz and lathosterolosis, respectively (Blassberg et al., 2016; Cooper et al., 2003; Horvat et al., 2011; Porter and Herman, 2011).