MELAS syndrome: causes, symptoms, diagnosis, treatment
Last reviewed: 23.04.2024
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MELAS syndrome (Mitochondrial Encephalomyopathy, Lactic Acidosis, Stroke-like episodes, mitochondrial encephalopathy, lactate acidosis, stroke-like episodes) is a disease caused by point mutations in mitochondrial DNA.
Symptoms of MELAS syndrome. The age at which the disease manifests varies widely from infant to adult, but most often the first symptoms appear in the period from 5 to 15 years. The onset of the disease is often characterized by stroke-like episodes, malignant migraines or delayed psychomotor development. Strokes are localized more often in the temporal, parietal or occipital areas of the brain, accompanied by hemiparesis and tend to be rapidly restored. They are caused by mitochondrial angiopathy, characterized by excessive proliferation of mitochondria in the walls of arterioles and capillaries of the brain vessels. As the disease progresses, against a background of repeated strokes neurological symptoms increase. Muscular weakness, convulsions, myoclonus, ataxia and neurosensory hearing loss are associated. Sometimes endocrine disorders develop (diabetes mellitus, pituitary fascism).
The survey includes biochemical, morphological and molecular-genetic studies. The most common mutation is the replacement of A by G in 3243 position. As a result, the transcriptional terminator inside the tRNA gene is inactivated . Consequently, as a result of single nucleotide replacement, the transcription ratio of rRNA and mRNA changes and the translation efficiency decreases. In second place in frequency there is a mutation of T to C in the 3271th position of mtDNA, leading to the development of MELAS syndrome.
[What tests are needed?
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