Bilirubin uridine diphosphate glucuronosyltransferase hepatic activity in jaundice associated with congenital hypothyroidism.

Hepatic bilirubin uridine diphosphate glucuronosyltransferase activity was assayed in an infant with prolonged jaundice and congenital hypothyroidism before thyroid therapy. This activity was nil, suggesting a possible delayed maturation of the enzyme. Although further studies will be necessary to confirm this hypothesis, prolonged jaundice associated with congenital hypothyroidism may be due to a delayed maturation of the hepatic glucuronidation of bilirubin.