Table 2.

Hereditary Disorders of Bilirubin Metabolism

Disorder	Mechanism	Total Serum Bilirubin Level (mg/dL)	Treatment
Gilbert’s syndrome	Mutation in UGT1A1 causing activity <33% normal	Up to 4	None
Crigler‐Najjar syndrome type 1	UGT1A1 activity absent	Usually 20‐40	Phototherapy
			Exchange transfusions
			Liver transplant
Crigler‐Najjar syndrome type 2	UGT1A1 activity <10% normal	Usually <20	Phenobarbital
DJ	MRP2 receptor mutation impairing transport across canalicular membrane	Usually 2‐5	None
Rotor syndrome	OATP1B1 and OATP1B3 mutations affecting reuptake of conjugated bilirubin by hepatocytes	Usually 2‐5	None