描述
Congenital Bile Acid Synthesis Defect Type III (CBASIII) is caused by a defect in 25-hydroxycholesterol 7-alpha-hydroxylase, which plays a role in synthesis of bile acids. The synthesis of primary bile acids from cholesterol occurs via two pathways: the classic neutral pathway involving cholesterol 7-alpha-hydroxylase (CYP7A1), and the acidic pathway involving a distinct microsomal oxysterol 7-alpha-hydroxylase (CYP7B1). CBASIII is characterized by accumulation of bile acids in the urine. Symptoms include severe cholestasis, cirrhosis, and liver failure.