Bhargava S, Ali A, Parakh R, Saxena R, Srivastava L M
Department of Biochemistry, Sir Ganga Ram Hospital, New Delhi, India.
Vascular. 2012 Apr;20(2):88-95. doi: 10.1258/vasc.2011.oa0320. Epub 2012 Feb 28.
Homocysteine is a sulfur-containing amino acid, which is derived from dietary methionine. Hyperhomocysteinemia has been implicated in vascular disease for over a decade now, and can be treated with B vitamins. Among its causes is polymorphism of the MTHFR gene, the most common being the cytidine to thymidine at position 677 (MTHFR C677T), which gives rise to three genotypes - normal homozygous CC, heterozygous CT and homozygous variant TT. An attempt was made to ascertain the prevalence of this MTHFR C677T in our population so that preventive measures may accordingly be instituted. Blood samples from 70 patients with vascular disease and 70 healthy controls were analyzed for plasma homocysteine levels (chemiluminescent immunoassay) and for the presence of MTHFR C677T (polymerase chain reaction analysis). Homocysteine was higher in the homozygous subjects (TT genotype) than in the heterozygous (CT genotype). In patients, the frequency of the C allele was significantly lower, and that of the T allele was significantly higher than the corresponding frequencies in controls. In conclusion, the North Indian urban population has higher homocysteine levels associated with the TT genotype. Hence, instituting measures towards reduction of homocysteine levels in the population would probably reduce the incidence and morbidity of vascular disease in our population.
同型半胱氨酸是一种含硫氨基酸，由饮食中的蛋氨酸衍生而来。高同型半胱氨酸血症与血管疾病的关联已达十余年，可用B族维生素进行治疗。其病因之一是亚甲基四氢叶酸还原酶（MTHFR）基因多态性，最常见的是第677位胞嘧啶突变为胸腺嘧啶（MTHFR C677T），由此产生三种基因型——正常纯合子CC、杂合子CT和纯合变异体TT。本研究旨在确定该MTHFR C677T在我国人群中的患病率，以便据此制定预防措施。对70例血管疾病患者和70例健康对照者的血样进行血浆同型半胱氨酸水平分析（化学发光免疫分析法）以及MTHFR C677T检测（聚合酶链反应分析法）。纯合子受试者（TT基因型）的同型半胱氨酸水平高于杂合子（CT基因型）。患者中，C等位基因频率显著低于对照组，而T等位基因频率显著高于对照组。总之，印度北部城市人群中与TT基因型相关的同型半胱氨酸水平较高。因此，采取措施降低人群中的同型半胱氨酸水平可能会降低我国人群血管疾病的发病率和患病率。
