Boers G H
Universitair Medisch Centrum St Radboud, afd. Algemene Interne Geneeskunde, Postbus 9101, 6500 HB Nijmegen.
Ned Tijdschr Geneeskd. 2001 May 19;145(20):956-8.
Homocysteine is a sulfhydryl containing amino acid which is produced as an intermediate product in the metabolism of the essential amino acid methionine. Apart from environmental factors such as the intake of folate and other B vitamins, the level of homocysteine in the blood is determined by the genetically based activities of several enzymes involved in the methionine or folate cycle. The well-known congenital defect homocystinuria is due to homozygosity for mutated cystathionine beta synthase. It is characterized by severe hyperhomocysteinemia, which leads to arterial and venous disease at a very young age. Mild to moderate hyperhomocysteinemia, due to either heterozygosity for severe mutations in the genes of enzymes involved or based upon homozygosity for more mild mutations, has also been recognized as a risk factor for vascular disease in the last decade. However, ongoing clinical intervention studies still need to demonstrate a casual role of mildly increased homocysteine levels in vascular disease.
同型半胱氨酸是一种含巯基的氨基酸，它作为必需氨基酸甲硫氨酸代谢的中间产物而产生。除了叶酸和其他B族维生素摄入等环境因素外，血液中同型半胱氨酸的水平由参与甲硫氨酸或叶酸循环的几种酶的基因活性决定。著名的先天性缺陷同型胱氨酸尿症是由于胱硫醚β合酶突变的纯合性所致。其特征为严重的高同型半胱氨酸血症，这会在非常年轻的时候导致动静脉疾病。在过去十年中，由于参与酶基因的严重突变的杂合性或更轻度突变的纯合性导致的轻度至中度高同型半胱氨酸血症，也被认为是血管疾病的一个危险因素。然而，正在进行的临床干预研究仍需证明同型半胱氨酸水平轻度升高在血管疾病中的因果作用。
