Gilbert Syndrome

Key Features

• Common form of familial hyperbilirubinemia present in 3–7% of the population

• Males are affected more often than females (4:1)

• Associated with a partial reduction of hepatic bilirubin uridine diphosphate-glucuronyl transferase activity

• Can occur following liver transplantation

Clinical Findings

• Affected infants may have more rapid increase in jaundice in the newborn period, accentuated breast milk jaundice, and jaundice with intestinal obstruction

• During puberty and beyond, mild fluctuating jaundice, especially with illness and vague constitutional symptoms, is common

• Shortened red blood cell survival in some patients is thought to be caused by reduced activity of enzymes involved in heme biosynthesis (protoporphyrinogen oxidase)

• Serum unconjugated bilirubin is generally < 3–6 mg/dL, although unusual cases may exceed 8 mg/dL

Diagnosis

• Findings on liver biopsy and most liver function tests are normal

• An increase of 1.4 mg/dL or more in the level of unconjugated bilirubin after a 2-day fast (300 kcal/d)

• Genetic testing is available but rarely needed

Treatment

• No treatment is necessary

• Phenobarbital (5–8 mg/kg/d) can reduce hyperbilirubinemia, but therapy is not justified