Abstract: 【Abstract】Objectives To summarize the characteristics of clinical manifestation，brain image and molecular genetics of mitochondrial eneephalomyopathy with lactic acidosis and stroke—like episode(MELAS) in children for improving diagnosis and management．Methods The clinical manifestation，laboratorial data，brain image，mitochondrial gene mutations，and mitochondrial complex I-V enzyme activity were analyzed in 7patients with MELAS．Their treatment and prognosis was evaluated by following up．Results The most common clinical presentations were stroke—like episode，seizures，headache and vomiting in the children with MELAS．Serum lactate level increased in all the cases．All patients showed low signal intensity on T1WI and hi【gh signal intensity on T2WI in brain image．The distribution of lesions Was multiple，and the most common lesions were located in the temporal lobe，parietal lobe and occipital lobe．Cerebral atrophy was found in the old lesions．The mtDNA gene mutational analysis showed A3243G mutation in white blood cells of 4 patients，the mutation rate varied from 29．7％to 60％．Mitochondrial complex I-V enzyme activity Was measured in peripheral leukocytes of 3 patients．Isolated complex I deficiency Was found in 2 cases，and a combined deficiency of complex I and Ⅳin one patient．All the patients had some degrees of mental retardation and needed antiepileptie treatment through following up．Conclusion Fully understanding the characteristics of clinical manifestation，laboratory tests，brain image，molecular features，and oxidative phosphorylation enzyme activity assay in children with MELAS Call be helpful to the early diagnosis and treatment．
2013, Vol. 1 
