3β-Hydroxy-Δ5-C27-Steroid Dehydrogenase Deficiency
Autosomal recessive
Caused by changes in both copies of HSD3B7, which encodes an early enzyme in the conversion of cholesterol to bile acids. Without it, normal bile acids are not made and abnormal intermediates build up and damage the liver.
Signs and symptoms
Most often presents in infancy with prolonged jaundice (cholestasis) and an enlarged liver, but with normal levels of the liver enzyme GGT. Poor absorption of fat and fat-soluble vitamins can cause poor growth, rickets and bleeding problems. Less often it first appears later in childhood or adulthood as liver disease or vitamin deficiency.
What a diagnosis changes
Oral bile acid therapy, such as cholic acid, normalises liver blood tests in most people treated, and works best when started early; untreated disease can progress to cirrhosis. Both parents are usually carriers, so genetic counselling and testing of siblings are recommended.
Genes analysed
Also known as
3-alpha beta-hydroxy-delta-5-C27-steroid oxidoreductase, deficiency of; 3-beta-hydroxy-delta-5-C27-steroid oxidoreductase deficiency type 1; BASD1; bile acid synthesis defect, congenital, 1; congenital bile acid synthesis defect type 1; CBAS1; congenital bile acid synthesis defect caused by mutation in HSD3B7; HSD3B7 congenital bile acid synthesis defect
