MELAS syndrome: causes, symptoms, diagnosis, treatment

MELAS syndrome (Mitochondrial Encephalomyopathy, Lactic 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 itself varies widely from infancy to adulthood, but most often the first symptoms appear between the ages of 5 and 15. The onset of the disease is often characterized by stroke-like episodes, malignant migraines, or psychomotor retardation. Strokes are most often localized in the temporal, parietal, or occipital regions of the brain, accompanied by hemiparesis and tend to recover quickly. 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 the background of repeated strokes, neurological symptoms increase. Muscle weakness, convulsions, myoclonus, ataxia, and sensorineural hearing loss join in. Endocrine disorders (diabetes mellitus, pituitary dwarfism) sometimes develop.

The examination includes biochemical, morphological and molecular genetic studies. The most common mutation is the replacement of A to G at position 3243. As a result, the transcriptional terminator contained within the tRNA gene is inactivated. Consequently, as a result of a single nucleotide replacement, a change in the transcriptional ratioof rRNA and mRNA occurs and the efficiency of translation decreases. The second most common mutation is the T to C mutation at position 3271 of mtDNA, leading to the development of MELAS syndrome.

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