Inborn Errors of Metabolism · USMLE Step 1

(MSUD) involves defective metabolism of which group of amino acids?

  1. Aromatic amino acids (phenylalanine, tyrosine, tryptophan)
  2. Sulfur-containing amino acids (methionine, cysteine)
  3. Branched-chain amino acids (leucine, isoleucine, valine)
  4. Basic amino acids (lysine, arginine, histidine)
Show answer and explanation

Correct answer: Branched-chain amino acids (leucine, isoleucine, valine)

MSUD results from defective activity of the branched-chain α-ketoacid dehydrogenase complex, impairing breakdown of the branched-chain amino acids leucine, isoleucine and valine.

Difficulty: Medium Question 3 of 19

Practice all 19 Inborn Errors of Metabolism questions

Keep practicing

More Inborn Errors of Metabolism questions