Disease or Syndrome
MELAS syndrome
Subclass of:
Brain Diseases, Metabolic, Inborn;
Mitochondrial Encephalomyopathies;
Cerebral Small Vessel Diseases
Definitions related to melas syndrome:
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A mitochondrial disorder characterized by focal or generalized seizures, episodes of transient or persistent neurologic dysfunction resembling strokes, and ragged-red fibers on muscle biopsy. Affected individuals tend to be normal at birth through early childhood, then experience growth failure, episodic vomiting, and recurrent cerebral insults resulting in visual loss and hemiparesis. The cortical lesions tend to occur in the parietal and occipital lobes and are not associated with vascular occlusion. VASCULAR HEADACHE is frequently associated and the disorder tends to be familial. (From Joynt, Clinical Neurology, 1992, Ch56, p117)NLM Medical Subject HeadingsU.S. National Library of Medicine, 2021
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A rare progressive neurodegenerative disorder characterized by mitochondrial myopathy, encephalopathy, lactic acidosis, and stroke-like episodes.NCI ThesaurusU.S. National Cancer Institute, 2021
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MELAS (mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episodes) is a multisystem disorder with protean manifestations. The vast majority of affected individuals develop signs and symptoms of MELAS between ages two and 40 years. Common clinical manifestations include stroke-like episodes, encephalopathy with seizures and/or dementia, muscle weakness and exercise intolerance, normal early psychomotor development, recurrent headaches, recurrent vomiting, hearing impairment, peripheral neuropathy, learning disability, and short stature. During the stroke-like episodes neuroimaging shows increased T2-weighted signal areas that do not correspond to the classic vascular distribution (hence the term "stroke-like"). Lactic acidemia is very common and muscle biopsies typically show ragged red fibers.GeneReviewsUniversity of Washington, 2021
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(mitochondrial encephalomyopathy, lactic acidosis and stroke) A maternally inherited condition characterized by mitochondrial myopathy, encephalopathy, lactic acidosis, and stroke-like episodes, caused by mutation(s) in one of several mitochondrial genes, most frequently the MT-TL1 gene, which encodes the mitochondrial transfer RNA for leucine.NICHD Pediatric TerminologyU.S. National Cancer Institute, 2021
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Mitochondrial myopathy, encephalopathy, lactic acidosis, and stroke (MELAS) syndrome is a progressive neurodegenerative disorder. Patients may present sporadically or as members of maternal pedigrees with a wide variety of clinical presentations.WebMD, 2019
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