A 22-year-old man comes to the physician 1 week after an episode of severe right flank pain that resolved with the passing of a renal calculus. His 25-year-old brother had similar symptoms 1 year ago. This patient most likely has an increased urine concentration of which of the following amino acids?

Question

Quizplus · Accepted Answer

The patient likely has cystinuria, a genetic disorder that leads to increased excretion of cystine, lysine, arginine, and ornithine in the urine, causing cystine stones. Cystinuria is a cause of persistent kidney stones (renal calculi). It is a disease involving the defective transepithelial transport of cystine and dibasic amino acids, such as lysine, in the kidney and intestine, and is one of many causes of kidney stones.

A 22-Year-Old Man Comes to the Physician 1 Week After