General anesthesia for patient with type III homocystinuria (tetrahydrofolate reductase deficiency).

Homocystinuria, a rare autosomal recessive genetic disease, is generally classified into 3 types (types I-III). Extremely rare type III is from a defect of the enzyme tetrahydrofolate reductase which converts homocysteine to methionine. The anesthetic problem of type III homocystinuria is the elevation of serum homocysteine and the deficiency of essential amino acid methionine, which result in the perioperative thromboembolic events and nitrous oxide-induced neurological impairment. We provided successful anesthetic management for a patient with type III homocystinuria, during which we were careful to take measures against perioperative thromboembolism and did not use nitrous oxide.