Snapshot A 24-year-old medical student is 2 weeks into her first surgery rotation when her senior resident tells her that her eyes look a little yellow. She experienced her first needle stick injury in the operating room just 1 week earlier and began to worry about hepatitis. Other than rarely having the time to eat at work, she has no other complaints or symptoms. Introduction Hereditary unconjugated hyperbilirubinemia due to defect in promotor gene for uridine diphosphoglucuronate-glucuronsyltransferase 1A1 (UGT1A1) conjugates bilirubin with glucuronic acid mild ↓ UDP-glucuronyl transferase activity mild ↓ bilirubin uptake Autosomal recessive inheritance very common in population Presentation Symptoms largely asymptomatic occasional reccurent mild jaundice associated with fasting, stress, and EtOH intake Studies Normal laboratory tests including hepatic function Isolated unconjugated hyperbilirubinemia serum bilirubin concentration is usually < 3 mg/dL Rifampin test can be used to diagnose Gilbert unconjugated bilirubin rises after a dose of rifampin (induces cytochrome P-450 and competes for excretory pathways in the liver) less specific to Gilbert as levels can rise in those with chronic liver disease (and not Gilbert) Treatment Benign condition No treatment required Complications Associated with increased risk of cholelithiasis Increased severity and duration of neonatal jaundice Drug-interaction and increased susceptibility to toxic effects with irinotecan