A 35-year-old male patient goes to the ER because he is troubled by his chronic fatigue and persistent abdominal discomfort. Additional signs in this patient are mildly icteric sclera. The ER attending calls for blood workup for bilirubin which shows the predominantly unconjugated form at a level of 2 mg/dL. The physician suspects the patient has Gilbert syndrome. Which of the following enzymes would be expected to be found at reduced levels if this is the correct diagnosis?

Question

Quizplus · Accepted Answer

Gilbert syndrome is characterized by a reduced level of the enzyme UDP-glucuronyltransferase, which leads to an increase in unconjugated bilirubin. Gilbert syndrome is characterized by mild, chronic unconjugated hyperbilirubinemia. The disorder results from mutations in the TATA-box of the promoter region upstream of exon 1 in the UGT gene which results in reduced levels of expression of a normal bilirubin UDP-glucuronyltransferase enzyme. The normal sequence of the UGT1A TATA-box is A(T_A)₆TAA, whereas in Gilbert syndrome individuals it is A(TA)₇TAA. Almost all afflicted individuals have a degree of icteric discoloration in the eyes typical of jaundice. Serum bilirubin levels in Gilbert syndrome patients are usually less than 3 mg/dL. Many patients manifest with fatigue and abdominal discomfort. Presentation of Gilbert syndrome symptoms occurs more frequently in men than in women because the production of bilirubin is higher in men.

A 35-Year-Old Male Patient Goes to the ER Because He