1984年Pavlakis等报告2例并从文献中查到9例具有几种共同特征的病例,即线粒体脑肌病,乳酸中毒和复发性卒中样发作(mitchondrial encephalomyopathy,lactic acidosis,and recurrent strokelike episodes,MELAS)。1990年Goto等报告多数MELAS患者存在线粒体DNA突变。这是一个影响tRNA转录亮氨酸的点突变(位于tRNA~(Leu(UUR))基因的第3243号位的核苷酸),据文献报道,这种点突变的发生率为60％～90％。以前报道的所有病例都是在尸检后和当时尚不能从遗传角度进行确诊时报告的。而该病卒中样发作 In 1984, Pavlakis et al reported 2 cases and found 9 cases with common features in the literature, namely mitochondrial encephalomyopathy, lactic acidosis and recurrent strokelike episodes (MELAS ). In 1990, Goto et al reported mitochondrial DNA mutations in most MELAS patients. This is a point mutation affecting the tRNA transcript leucine (located at nucleotide 3243 of the tRNA ~ (Leu) gene). It has been reported in the literature that the incidence of this point mutation is 60% ~ 90 %. All previously reported cases were reported after the autopsy and at the time were not yet diagnostically diagnosed. The stroke-like attack