The function of NSDHL (NAD(P) dependent 3-beta-hydroxysteroid dehydrogenase NSDHL, Ensembl gene identifier ENSG00000147383) is as follows. Catalyzes the NAD(P)(+)-dependent oxidative decarboxylation of the C4 methyl groups of 4-alpha-carboxysterols in post-squalene cholesterol biosynthesis (By similarity). Also plays a role in the regulation of the endocytic trafficking of EGFR (By similarity). .