Disorders of Bile Acid Synthesis

Progressive intrahepatic cholestasis may be caused by deficiencies in enzymes of bile acid synthesis, resulting in accumulation of toxic metabolites (-5-sulfate bile acids). Three  such disorders have been described:
·	1-3--hydroxy-C27-steroid dehydragenase/isomerase &
·	2-4-3 oxosteroid 5 -reductase &
·	oxysterol 7 -hydroxylase &
which result in cholestasis without itching, normal serum gammaglutamiltransferase activity, and low serum bile acid levels.
Early diagnosis, based on FAB Gas chromatography-mass spectrometry of urine, and prompt treatment with primary bile acids and ursodeoxycholic acid may allow normalization of liver function.
In the past, when these defects were not known, patients with deficiencies of bile acid synthesis were diagnosed to have type 2 Byler’s disease, and some of them were probably treated with liver transplantation.