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MELAS syndrome


MELAS syndrome (Mitochondrial Encephalomyopathy, Lactic Acidosis, Stroke-like episodes, mitochondrial encephalopathy, a lactacidemia, insultopodobny episodes) - the disease caused by point mutations in mitochondrial DNA.

Пациентка с синдромом MELAS

The patient with MELAS syndrome

MELAS syndrome reasons:

The syndrome is connected with mutations in many genes: MTTL1, MTTQ, MTTH, MTTK, MTTS1, MTND1, MTND5, MTND6, MTTS2. Mutations can arise for the first time at the specific patient, or be inherited on the maternal line. In total by 2009 23 missensny dot mutations and 4 deletions мтДНК, leading to MELAS were revealed, however messages on new patients with frustration symptoms in the absence of the known mutations proceed.

MELAS syndrome symptoms:

The age at which demonstrates a disease widely varies from infantile to the adult, however most often the first symptoms appear in the period from 5 to 15 years. The onset of the illness is often characterized by insultopodobny episodes, malignant migraines or a delay of psychomotor development. Strokes are localized more often in temporal, parietal or occipital areas of a brain, are followed by a hemiparesis and tend to bystry recovery. They are caused by the mitochondrial angiopatiya which is characterized by excess proliferation of mitochondrions in walls of arterioles and capillaries of vessels of a brain. In process of progressing of a disease, against the background of repeated strokes the neurologic symptomatology accrues. Muscular weakness, spasms, myoclonias, an ataxy and neurosensory relative deafness join. Sometimes endocrine frustration (a diabetes mellitus, a pituitary nanism) develop.

The syndrome of MELAS is followed by polymorphic symptomatology — diabetes, spasms, decrease in hearing, heart diseases, low growth, endocrinopathies, intolerance of exercise stresses and neuropsychiatric deviations.


Inspection includes carrying out biochemical, morphological and molecular and genetic researches. The most frequent mutation - replacement And by G in the 3243rd situation. The transkriptsionny terminator imprisoned in TRNK gene is as a result inactivated. Therefore, change of a transkriptsionny ratio of RRNK and MRNK and decrease in efficiency of broadcasting is caused by one-nucleotide replacement. On frequency the T mutation on With in the 3271st situation мтДНК, MELAS leading to development of a syndrome is on the second place.

«Рваные (шероховатые) красные мышечные волокна» при синдроме MELAS — аномальное скопление митохондри

"Fragmentary (rough) red muscle fibers" at MELAS syndrome — abnormal accumulation of a mitochondrion

Treatment of a syndrome of MELAS:

Treatment of a syndrome is not known yet, often it utyagoshchatsya, leading as a result to death of the patient. Attempts to slow down its current are made. Use of L-arginine for reduction of injuries of a brain at insultopodobny episodes is investigated, and researchers report that before drug acceptance the level of arginine in blood of patients was considerably reduced during episodes. Preliminary results encourage, however additional researches are necessary. L-arginine provokes NO allocation - the gas having both positive effect - vasodilatation, and negative: surplus can be toxic. It is known, for example, that at a heart attack L-arginine initially showed positive takes, however larger and long researches did not confirm early finds and besides revealed the increased mortality among those who accepted this means.

Also Q coenzyme, for lack of results of adequate clinical trials is applied; such researches are begun, but not completed as of the end of 2009 yet.

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