Crigler-Najjar syndrome is a rare form of congenital non-haemolytic hyperbilirubinaemia.
Type I Crigler-Najjar syndrome is characterised by a total deficiency of hepatic glucuronyl transferase. It is inherited as an autosomal recessive. Conjugated bilirubin is absent from the serum. The majority die with kernicterus in the first year of life. Phototherapy can reduce the serum bilirubin by 50% and may be performed at home.
Type II Crigler-Najjar syndrome is characterised by a partial deficiency of glucuronyl transferase. It is inherited as an autosomal dominant. Patients given phenobarbital often survive into adult life. Phototherapy may be used to lower the serum bilirubin level.