Résumé :
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Communication n° 114. Introduction : One of the most common of mtDNA mutations is the 3243A>G mutation of the tRNALeu(UUR) gene associated with Mitochondrial Encephalomyopathy, Lactic Acidosis and Stroke-like episodes (MELAS). This acronym summarized the cardinal feature of the disease. Here we report a case of intestinal pseudo-obstruction as prominent feature of MELAS. Observation : This 56 year old man had a non insulinodependant diabetes and deafness. He developed in July 2004 a right hemiparesis that was regressive. One month latter, two paralytic ileus were diagnosed. Several complementary exams, including surgical examination of the abdomen, failed to find aetiology and intestinal pseudo-obstruction was diagnosed. Regarding his history, genetic analysis of mtDNA was performed that revealed the presence of the A3243G heteroplasmic mutation in blood that confirmed the diagnosis of MELAS syndrome. Muscle biopsy showed several Ragged Red Fibres (RRF) that were strongly positive to Succinate Dehydrogenase (SDH) staining and numerous c-cytochrome (COX) negative fibres. Discussion and conclusion : The cardinal features of MELAS that lead to its characterisation are rarely associated with intestinal symptoms. The latter can even be the principal signs and myopathy and strokes-like episodes may be ignored. In those cases, most of them present with intestinal pseudo-obstruction but other symptoms such as acute pancreatitis have been described. Electron microscopy examination of smooth muscle cells shows numerous abnormal, enlarged mitochondria. This energy defect of the intestinal wall is likely responsible for the intestinal dysmotility. We suggest that MELAS must be suspected when intestinal syndromes that failed to be related to aetiology are associated with multisystemic diseases.
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