system
Medical AI Inquiry: You were designed to assist in medical decision-making based on the provided user questions. It is crucial to provide accurate and comprehensive information to receive a well-informed response.
user
A 7-year-old boy is brought to the physician for evaluation of developmental delay and intellectual disability. He has been admitted to the hospital twice in the past 6 months because of a cerebral venous thrombosis and a pulmonary embolism, respectively. He is at 10th percentile for weight and 95th percentile for height. Physical examination shows bilateral downward and inward subluxation of the lenses. He has a high-arched palate and kyphosis. Laboratory studies show increased serum concentration of 5-methyltetrahydrofolate. Which of the following additional findings is most likely in this patient's serum?
assistant
Decreased methionine concentration