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Biochemistry 10

A 36-year-old man with intellectual disability is referred to a vascular surgeon due to the presence of severe popliteal artery plaques. On physical examination, the patient is noted to have above average height, and an eye exam reveals downward lens dislocation. Laboratory tests reveal elevated methionine and homocysteine levels.

In which of the following is the patient most likely deficient?

  • A) Cystathionine synthase
  • B) Homocysteine methyltransferase
  • C) Methionine synthase
  • D) Vitamin B9
  • E) Vitamin B12


Austinn Miller


Dr. Ted O'Connell