Monarch Disease Ontology id MONDO_0013439 (congenital bile acid synthesis defect 3) is congenital bile acid synthesis defect type 3 (BAS defect type 3) is a severe anomaly of bile acid synthesis characterized by severe neonatal cholestatic liver disease. Also known as: BASD3, CBAS3, CYP7B1 congenital bile acid synthesis defect, bile acid synthesis defect, congenital, type 3, congenital bile acid synthesis defect caused by mutation in CYP7B1, congenital bile acid synthesis defect type 3, oxysterol 7-alpha-hydroxylase deficiency.