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MELAS syndrome: symptoms, causes and treatment

MELAS syndrome: symptoms, causes and treatment

August 11, 2022

Within the diseases categorized as rare, we find MELAS Syndrome, a strange condition which, in Spain, only affects less than 5 per 100,000 people over 14 years of age. This alteration of mitochondrial origin seriously affects the neurological functioning of the person and its symptoms are manifested until the moment of death.

Throughout this article we will describe in detail what this hereditary disease consists of, as well as what its symptoms are, where the origin of the condition is and how the possible treatments are carried out.

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What is MELAS syndrome?

MELAS syndrome is a rare hereditary mitochondrial disease whose main characteristic is the generation of a series of neurological alterations . The conditions of mitochondrial category provoke in the person certain neurological disorders caused by a mitochondrial genomic mutation.


Mitochondria are cytoplasmic organelles formed by eukaryotic cells, whose main mission is to generate energy through the consumption of oxygen. This organelle is essential for the metabolism of our cells, so any alteration in it can cause serious complications in the health and quality of life of the person.

This syndrome was first described in 1975, but it was not until 1984 that it received its current name. The term MELAS consists of an acronym of its most distinctive clinical properties:

  • ME: Mitochondrial encephalomyopathy (mitochondrial encephalomyopathy).
  • LA: Lactic acidosis (lactic acidosis).
  • S: Episodes Stroke-like (Stroke-like episodes).

In its first description, the MELAS syndrome was described as a set of convulsive incidents, gradual degeneration of language, lactic acidosis and tearing of muscle fibers .


The first symptoms of this condition usually appear during childhood or adolescence, especially between 2 and 5 years. Although the development of the disease can vary considerably among those who suffer from it, the prognosis tends to be quite reserved in the vast majority of cases; since the patients develop serious health complications until they die.

Regarding the incidence of MELAS syndrome, this is a very unusual condition among the population. Although specific data on its prevalence have not been established, it is known that is one of the most common mitochondrial diseases . On the other hand, a higher prevalence has not been demonstrated in men or in women, nor in any specific ethnic or racial group.

What is the clinical picture?

As we have pointed out previously, MELAS Syndrome is distinguished by having the main characteristics that make up its clinical picture and differentiates it from other mitochondrial diseases.


1. Mitochondrial encephalomyopathy (ME)

The encephalomiopatías are those diseases whose origin is in alterations in the structure and functioning of the central nervous system, which have to cause quite frequent convulsive episodes.

These episodes consist of temporally delimited events during which the person undergoes exaggerated motor agitation, spasmodic and involuntary muscular activity and changes in the state of consciousness and perception. A distinction can be made between focal crises or generalized crises . In focal seizures, abnormal brain electrical activity is usually restricted to a specific area of ​​the brain, while in generalized areas discharge patterns extend to various brain areas.

The danger of these epileptic crises lies in the risk that the different brain structures affected are permanently damaged, generating serious consequences at the cognitive and motor level.

2. Lactic acidosis (LA)

The lactic acidosis present in MELAS Syndrome consists of a abnormal accumulation of lactic acid . When this substance, generated mainly in red blood cells and muscle cells, agglomerates pathologically can lead to a series of very serious health problems that can end up causing the death of the patient.

The main signs indicating an accumulation of lactic acid include vomiting, diarrhea, nausea, gastric pain, prolonged drowsiness over time , alterations in the state of consciousness, respiratory problems, hypotension, dehydration and deficits in the blood and oxygen supply to muscles, tissues and organs.

3. Stroke-like (S)

The stroke-like concept refers to Stroke-like events or brain strokes .

A cerebrovascular accident is a focal and spontaneous event in which the flow of blood in a specific area of ​​the brain is interrupted. When this happens for more than a few seconds, the brain cells begin to deteriorate and die due to lack of oxygen and nutrients.

The main consequences of these cerebrovascular accidents are alterations in the visual system, in the language and in the motor aspect, as well as a gradual cognitive deterioration that can get to cause a dementia .

What symptoms does it present?

In MELAS Syndrome, the clinical picture described above is accompanied by symptoms that, although they occur very differently among patients, usually appear in the vast majority of cases.

These symptoms include:

  • Migraines and headaches recurrent
  • Nausea and vomiting.
  • Anorexy.
  • Cognitive impairment gradual.
  • Generalized delay in development.
  • Problems in learning and attention deficits.
  • Alterations in the state of consciousness.
  • Muscular and motor pathologies as chronic fatigue, muscle weakness or hypotonia.
  • Pathologies in the visual system such as optic atrophy, retinitis or diminished visual acuity.
  • Sensorineural deafness .
  • Extreme sensitivity to temperature changes.

Other less common symptoms, but which may also appear during the course of the disease, are those related to the person's mental and psychological state. These symptoms can be:

  • Aggressive behavior
  • Alterations of the personality.
  • Obsessive-Compulsive Disorder
  • Anxious disorders.
  • Psychosis.
  • Affective alterations.

What causes does it have?

As mentioned at the beginning of the article, MELAS Syndrome is a disease caused by a mutation in mitochondrial DNA . Therefore, it is a hereditary condition that is transmitted from the maternal genes.

These alterations occur in a series of specific genes located in the genetic material of the mitochondria. Most of these specific genes are responsible for transforming oxygen, sugars and fats into energy; while some others are involved in the production of tRNA molecules responsible for the construction of amino acid structures.

What is the treatment and prognosis?

At the moment, no specific treatment has been developed for MELAS Syndrome, otherwise specific treatments are made for each of the symptoms that presents in patient, as well as a series of palliative care to improve their quality of life.

Within the usual protocol, a group of specialists, including neurologists, cardiologists, ophthalmologists, or endocrinologists, among many others, is responsible for developing a specialized treatment that adapts to the patient's symptoms and needs.

Unfortunately, these treatments are not able to completely alleviate the effects of this condition, so the person usually presents progressively a cognitive impairment, followed by psychomotor problems, decreased hearing and visual abilities, and a whole series of medical complications until the death of the patient.


MELAS Syndrome : Causes, Diagnosis, Symptoms, Treatment, Prognosis (August 2022).


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