HSD3B7 and cholestasis: Inborn errors of primary bile acid (BA) synthesis disorder is a rare autosomal recessive disease, accounting for 1% to 2% of unexplained cholestasis in newborns and children.[1] The deficiency of 3β-hydroxy-Δ5-C27-steroid dehydrogenase (3β-HSD) due to mutations in gene HSD3B7, is the most common type of primary BA synthesis disorder.[2] The prevalence of 3β-HSD deficiency could be estimated as 1 case per 10 million.[3] Affected individuals show cholestasis, hepatomegaly, splenomegaly and fat (-soluble vitamins) malabsorption, with or without pruritus.