Sorted By Test Name - Mayo Medical Laboratories

UGT2O
60350
Reference Values:
An interpretive report will be provided.
Clinical References: 1. Guilemette C: Pharmacogenomics of human UDP-glucuronosyltransferase
enzymes. Pharmacogenomics J 2003;3:136-158 2. Innocenti F, Grimsley C, Das S, et al: Haplotype
structure of the UDP-glucuronosyltransferase 1A1 promoter in different ethnic groups. Pharmacogenetics
2002;12:725-733 3. Costa E, Vieira E, Martins M, et al: Analysis of the UDP-glucuronosyltransferase
gene in Portuguese patients with a clinical diagnosis of Gilbert and Crigler-Najjar syndromes. Blood Cells
Mol Dis 2006;36:91-97 4. Kitagawa C, Ando M, Ando Y, et al: Genetic polymorphism in the
phenobarbital-responsive enhancer module of the UDP-glucuronosyltransferase 1A1 gene and irinotecan
toxicity. Pharmacogenet Genomics 2005;15:35-41
UDP-Glucuronosyl Transferase 1A1 (UGT1A1), Full Gene
Sequencing, Hyperbilirubinemia, Saliva
Clinical Information: Bilirubin, resulting from the breakdown of heme, is a water-insoluble toxic
compound. Uridine diphosphate (UDP)-glycuronosyl transferase 1A1 (UGT1A1) is responsible for
bilirubin conjugation with glucuronic acid. This renders the bilirubin water soluble and permits excretion
of the bilirubin-glucuronide conjugates in urine.(1) Genetic mutations in the UGT1A1 gene may cause
reduced or absent UGT1A1 enzymatic activity resulting in hyperbilirubinemia (eg, Gilbert syndrome,
Crigler-Najjar syndrome). Gilbert syndrome, found in 5% to 10% of the population, is the most common
hereditary cause of increased bilirubin and is associated with mild hyperbilirubinemia (bilirubin levels are
typically around 3 mg/dL).(2) Gilbert syndrome is caused by a 25% to 50% reduced glucuronidation
activity of the UGT1A1 enzyme and characterized by episodes of mild intermittent jaundice and the
absence of liver disease. Crigler-Najjar (CN) types I and II are inherited causes of severe unconjugated
hyperbilirubinemia. CN type I is associated with no UGT1A1 enzymatic activity and usually presents as
intense jaundice in the first days of life and persists thereafter.(3) Type II is a milder form in which
bilirubin levels are