Objective: To improve the understanding of mitochondrial encephalomyopathy with lactic acidosis and stroke-like episode (MELAS) syndrome in clinical practice.

Methods: The clinical diagnosis and treatment of one patient with MELAS syndrome were reported. The clinical manifestations, diagnosis and possible mechanism of MELAS syndrome were discussed based on literature review.

Results: One patient with MELAS syndrome manifested first-onset stroke attack, and then appeared epileptic seizures. Suspicious antibodies in cerebrospinal fluid and serum were negative. The result of mitochondrial disease gene detection revealed m.3243A>G, and the final diagnosis was MELAS syndrome.

Conclusion: MELAS syndrome is one of the most common type of mitochondrial myopathy, which can influence multiple systems, including brain and muscle tissues. The clinical manifestations of MELAS syndrome are various and lack of a unified diagnostic standard, so it is easy to escape diagnosis or be misdiagnosed, and the prognosis is poor. Therefore, it is very important to recognize MELAS syndrome early, in order to make the diagnosis as soon as possible and give appropriate treatment to improve the prognosis of patients.