What condition is associated with the buildup of methionine and homocysteine in plasma?

What condition is associated with the buildup of methionine and homocysteine in plasma?

• A. Alkaptonuria
• B. Homocystinuria
• C. Cystinuria
• D. Tyrosinemia

Answer: (B)

The condition associated with the buildup of methionine and homocysteine in plasma is homocystinuria. This genetic disorder is caused by a deficiency in enzymes involved in the metabolism of methionine, most commonly cystathionine beta-synthase. When this enzyme is not functioning properly, it leads to the accumulation of homocysteine and its precursors, including methionine, in the bloodstream.

Homocystinuria can result in a variety of clinical manifestations, including developmental delays, cardiovascular issues, skeletal abnormalities, and increased risk for thromboembolic events. The diagnosis of this condition is typically made through specific biochemical tests that reveal elevated levels of homocysteine and methionine, supporting the diagnosis and guiding further management.

Understanding this connection highlights the importance of enzyme pathways in amino acid metabolism and the systemic effects that can arise from genetic deficiencies in these processes.