MELAS综合征一家系5例报告及特点分析

Analysis of a Chinese family with mitochondrial encephalomyopathy, lactic acidosis and stroke -like episodes

目的探讨线粒体脑肌病伴高乳酸血症和卒中样发作（MELAS）综合征的临床、影像学及遗传学特点，以提高对疾病的认识及诊断水平。方法对一家系临床确诊的5例患者资料进行收集及回顾性分析，包括患者基本资料、临床表现、血液生化、肌电图、突变位点及线粒体DNA（mtDNA）A3243G突变率等。结果5例患者均为慢性病程，以癫痫、卒中样发作、偏头痛、肌无力为主要表现，伴有糖尿病、耳聋等多系统损害，血清肌酶轻度增高或正常，头颅核磁共振成像显示病变多位于颞叶、顶叶、枕叶皮质及皮质下，呈脑回状，具有多灶性、非对称性、游走性、不按血管分布特点，磁共振灌注成像病变区呈现高灌注和血管源性水肿。头颅磁共振波谱可见倒置乳酸峰。mtDNA A3243G基因位点突变阳性。结论线粒体脑肌病是一种母系遗传病，多合并mtDNA A3243G突变，尽早识别典型的临床、影像及遗传特点有助于提高对其诊断水平。

Objective To investigate the manifestation, and the radiographic and genetic features of a family with mitochondrial encephalomyopathy, lactic acidosis and stroke -like episodes （MELAS）, and to strengthen the capacity to diagnose this syndrome. Methods Data from a five - member family were retrospectively analyzed, including personal information, clinical manifestation, biological test, electromyography, site mutation and the mutation rate of mtDNA A3243G. Results Five patients showed chronic symptoms, mainly epilepsy, stroke -like episodes, migraine and amyo- tonia, as well as damages in muhiple systems like diabetes and loss of hearing. Their levels of creatinase were normal or slightly increased. According to cerebral MR, the injuries mainly located at the temporal, parietal and occipital cortex and sub - cortex were muhifocal and asymmemtrieal, with a shape of gyms and easy to migrate, which did ilot distribute alol^o the vessels. Perfusion -weighted MRI indicated hyperperfusion and vasogenic edema in the damaged region, where Lac peaks were visible. Positive mutation at mtDNA A3243G was determined. Conclusion MELAS is a genetic syn- drome inherited through the maternal side, which is often seen in combination with mutation at mitochondrial A3243G site. Early recognition of typical clinical images and genetic characteristics will help give a correct diagnosis.