RÉSUMÉ
Objective:To explore the clinical and imaging characteristics of mitochondrial encephalomyopathy with lactic acidosis and stroke-like episodes (MELAS) caused by mitochondrial DNA 14453G>A (m.14453G>A) mutation.Methods:A case of MELAS caused by m.14453G>A mutation in the First Affiliated Hospital of Harbin Medical University on October 12, 2021 was reported. At the same time, the reported cases of MELAS and Leigh syndrome (LS) caused by the m.14453G>A mutation were reviewed. This enabled a comprehensive summarization, analysis, and comparison of these cases.Results:The patient was a female. She has suffered from the disease since 13-year old with seizures, accompanied by the disturbance of mood and the loss of memory. Brain magnetic resonance imaging findings consisted of lesions in frontal, parietal, occipital, temporal lobe and cerebellar. The patient was initially considered with autoimmune encephalitis and posterior reversible encephalopathy syndrome. Since direct sequencing of the complete mitochondrial genome from blood of the patient revealed m.14453G>A mutation in ND6 gene, and the mutation rate was 17.0%, the patient eventually diagnosed with MELAS based on clinical manifestations, imaging examinations, and genetic testing results. Using "m.14453G>A" as the search term, the relevant literature in China and abroad was retrieved and those with complete clinical data were identified. A total of 11 cases of m.14453G>A mutation including this case were reported, of whom 5 patients were diagnosed as MELAS, and 6 patients were diagnosed as LS. Among the 11 patients, those being adolescent or adult and with lesions in the cortex and subcortical white matter were probably be MELAS; those being infant or young child and with lesions in basal ganglia, thalamus and brainstem could be LS. Conclusions:Mitochondrial disease caused by m.14453G>A gene mutation shows a great heterogeneity, which can cause MELAS and LS. The clinical phenotype of the m.14453G>A mutation may be related to the age of onset and lesion′ s location.