A 30-year-old man comes to the ER because he has had constant severe pain in his right ankle over the past 24 hours. His uncle also had episodes of pain in single joints. The ankle is swollen and warm. Serum uric acid concentration is increased. Which of the following enzyme activities is most likely to be decreased in this patient?

Question

Quizplus · Accepted Answer

The patient's symptoms and family history suggest gout, which is often associated with decreased activity of hypoxanthine guanine phosphoribosyltransferase (HGPRT). This enzyme deficiency leads to increased uric acid production, causing gout.  Gout is characterized by elevated levels of uric acid in the blood and urine. Uric acid is the end product of purine catabolism and excess production results from a variety of metabolic abnormalities that lead to overproduction of purines via the de novo pathway. Uric acid is very insoluble and when generated in large amounts will precipitate as uric acid crystals in the joints of the extremities. There are at least 3 different inherited defects that lead to early development of severe hyperuricemia and gout. One of these is deficiency in the purine salvage enzyme, hypoxanthine-guanine phosphoribosyltransferase (HGPRT).

A 30-Year-Old Man Comes to the ER Because He Has