Gilbert's Syndrome (UGT1A1)

Gilbert’s syndrome is characterised by jaundice due to increased levels of unconjugated plasma bilirubin. Men are at higher risk than females and usually present post-puberty. In people of northern European ancestry, cases of Gilbert’s syndrome are often associated with inheriting two copies (one from each parent) of a specific mutation in the promoter region of the gene encoding the enzyme glucuronyltransferase (UGT1A1), designated UGT1A1*28 allele. UGT1A1 is a liver enzyme important for clearing conjugated bilirubin from the circulation. In general, other than the low grade elevated bilirubin levels, people with Gilbert’s syndrome exhibit no other signs or symptoms. In some cases, toxicity therapeutic agents, such as anticancer agent irinotecan and anti-viral protease inhibitor Indinivar, may occur in patients with Gilbert’s syndrome. Testing for Gilbert’s syndrome may assist in differentiating the cause of isolated elevated bilirubin levels in those patients with normal test results for FBC, reticulocytes, haptoglobin and liver enzymes.