All of the following amino acids are excreted in cystinuria, EXCEPT:
High-Yield Explanation
Cystinuria is an autosomal recessive disorder caused by defective transpoers in the apical brush border of proximal renal tubule and small intestinal cells. It is characterized by impaired reabsorption and excessive urinary excretion of the dibasic amino acids lysine, arginine, ornithine, and cystine. Because cystine is poorly soluble, its excess excretion predisposes to the formation of renal, ureteral, and bladder stones. Such stones are responsible for the signs and symptoms of the disorder. Ref: Longo N. (2012). Chapter 365. Inherited Defects of Membrane Transpo. In D.L. Longo, A.S. Fauci, D.L. Kasper, S.L. Hauser, J.L. Jameson, J. Loscalzo (Eds), Harrison's Principles of Internal Medicine, 18e.