Rosenblatt D S, Lue-Shing H, Arzoumanian A, Low-Nang L, Matiaszuk N
Hess B. and Diane Finestone Laboratory, Department of Medicine, McGill University, Montreal, Quebec, Canada.
Biochem Med Metab Biol. 1992 Jun;47(3):221-5. doi: 10.1016/0885-4505(92)90029-x.
Methylenetetrahydrofolate reductase (MR) deficiency is the most common inborn error of folate metabolism with more than two dozen patients described. The phenotypic spectrum ranges from severe neurological deterioration and early death to asymptomatic adults. Some patients with a severe deficiency of MR have been shown to have thermolabile reductase at 55 degrees C. Since methyltetrahydrofolate, the product of MR, is a methyl donor for methylcobalamin (MeCbl), the cofactor for methionine synthase (MS), we have looked at MeCbl accumulation and MS activity in fibroblasts from 15 patients with MR deficiency. Thermolabile MR was most often but not always seen in later onset disease. MeCbl levels were often lowest in the patients with early onset disease. All but two patients had levels of methionine synthase within the control range.
亚甲基四氢叶酸还原酶（MR）缺乏症是叶酸代谢中最常见的先天性缺陷，已有二十多名患者被报道。其表型范围从严重的神经功能恶化和早期死亡到无症状的成年人。一些严重缺乏MR的患者已被证明在55摄氏度时还原酶不耐热。由于MR的产物甲基四氢叶酸是甲硫氨酸合成酶（MS）的辅因子甲钴胺（MeCbl）的甲基供体，我们研究了15例MR缺乏症患者成纤维细胞中的MeCbl积累和MS活性。不耐热的MR最常见于晚发型疾病，但并非总是如此。早发型疾病患者的MeCbl水平通常最低。除两名患者外，所有患者的甲硫氨酸合成酶水平均在对照范围内。
