Freeman J M, Finkelstein J D, Mudd S H
N Engl J Med. 1975 Mar 6;292(10):491-6. doi: 10.1056/NEJM197503062921001.
Homocystinuria and homocystinemia without hypermthioninemia, but with reccurent episodes of folate responseive schizophrenic-like behavior, was documented in a mildly retarded adolescent girl who lacked the habitus associated with cystathionine synthase deficiency. Enzymes involved in homocysteine-methionine metabolism were demonstrated to be normal. A defect in the ability to reducte N-5-10--methylenetetrahydrofolate to 5-methyltetrahydrofolate was demonstrated. Methylenetetrahydrofolate reductase was 18 per cent of control values. Methyltetrahydrofolate is used for the methylation of homocysteine to methionine, and a deficiency of this compound could explain the homocystinemia and homocystinuria.
在一名轻度智力发育迟缓的青春期女孩中记录到同型胱氨酸尿症和同型高胱氨酸血症，无高甲硫氨酸血症，但伴有叶酸反应性精神分裂症样行为的反复发作，该女孩没有与胱硫醚合成酶缺乏相关的体型。参与同型半胱氨酸 - 甲硫氨酸代谢的酶被证明是正常的。已证明将N - 5,10 - 亚甲基四氢叶酸还原为5 - 甲基四氢叶酸的能力存在缺陷。亚甲基四氢叶酸还原酶为对照值的18%。5 - 甲基四氢叶酸用于将同型半胱氨酸甲基化为甲硫氨酸，这种化合物的缺乏可以解释同型高胱氨酸血症和同型胱氨酸尿症。
