The bile acids, cholic acid and chenodesoxycholic acid, are synthesised in the liver from cholesterol. They are then esterfied and conjugated with glycine or taurine to form bile salts and excreted into the bile. There are three known, very rare, disorders of bile acid synthesis which classically present as prolonged neonatal jaundice and associated liver disease; signs and symptoms (steatorrhoea, failure to thrive, conjugated hyperbilirubinemia, elevated LFTs, normal GGT, low fat soluble vitamins). Specific testing of urine bile acids is diagnostic of the conditions.
As bile acids are synthesised in the cell peroxisomes urine bile acids can also be used as part of the work-up of a suspected peroxisomal disorder.