In diseases classified as rare we find MELAS syndrome, a strange condition which, in Spain, concerns only 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 inherited disease is, along with its symptoms, where the source of the disease is located, and how possible treatments are carried out.
What is MELAS syndrome?
MELAS syndrome is a strange inherited mitochondrial disease whose main characteristic is the generation of a number of neurological disorders. Conditions in the mitochondrial category cause certain neurological disorders in the person caused by a mitochondrial genomic mutation.
Mitochondria are cytoplasmic organelles formed by eukaryotic cells, the main mission is to generate energy by consuming oxygen. This organelle is essential for the metabolism of our cells, so any alteration in it can lead to serious complications on 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 for its most distinctive clinical properties:
- ME: mitochondrial encephalomyopathy (mitochondrial encephalomyopathy).
- L ‘: lactic acidosis.
- S: stroke-type episodes.
In its first description, MELAS syndrome was described as a set of seizures, progressive degeneration of the tongue, lactic acidosis and tearing of muscle fibers.
The first symptoms of this condition usually appear during childhood or adolescence, especially between the ages of 2 and 5. Although the development of the disease can vary widely among those who suffer from it, the prognosis tends to be quite reserved in the vast majority of cases; because patients develop serious health complications until their death.
As for the incidence of MELAS syndrome, it is a very rare condition in the population. Although no specific data have been established on its prevalence, it is known that it is one of the most common mitochondrial diseases. In contrast, no higher prevalence has been demonstrated in males or females, or in any particular ethnic or racial group.
What is the clinical picture?
As we pointed out above, MELAS syndrome is distinguished by its main features that make up its clinical picture and differentiate it from other mitochondrial diseases.
1. Mitochondrial encephalomyopathy (ME)
Encephalomyopathies are diseases whose origin is alterations in the structure and functioning of the central nervous system, which must cause quite frequent seizures.
These episodes consist of temporarily delimited events in which the person suffers from exaggerated motor restlessness, spasmodic and involuntary muscle activity, and changes in state of consciousness and perception. A distinction can be made between focal seizures and generalized seizures. In focal seizures, the abnormal electrical activity of the brain is usually limited to a specific area of the brain, while in generalized discharge patterns spread to various areas of the brain.
The danger of these epileptic seizures lies in the risk that the various brain structures affected are permanently damaged, generating serious cognitive and motor consequences.
2. Lactic acidosis (LA)
Lactic acidosis present in MELAS syndrome consists of a abnormal buildup of lactic acid. When this substance, generated mainly in red blood cells and muscle cells, pathologically aggregates it can lead to a series of very serious health problems that can ultimately lead to the death of the patient.
The main signs that indicate a buildup of lactic acid include vomiting, diarrhea, nausea, stomach pain, prolonged drowsiness over time, Alterations in consciousness, breathing problems, hypotension, dehydration and deficiencies in the blood and oxygen supply to muscles, tissues and organs.
3. Like a blow (S)
The concept in the form of a line refers to stroke-like events or stroke.
A stroke is a focal, spontaneous event that disrupts blood flow to a specific area of the brain. When this happens for a little more than a few seconds, brain cells begin to deteriorate and die due to lack of oxygen and nutrients.
The main consequences of these strokes are alterations in the visual system, language and motor appearance, as well as progressive cognitive impairment which can come cause dementia.
What are the symptoms?
In MELAS syndrome, the clinical picture described above is accompanied by symptoms which, although very different in patients, usually appear in the vast majority of cases.
These symptoms include:
- Migraines and headaches recurrent.
- Nausea and vomiting.
- cognitive impairment gradual.
- Generalized developmental delay.
- Learning problems and attention deficits.
- Alterations in the state of consciousness.
- Muscular and motor pathologies such as chronic fatigue, muscle weakness or hypotonia.
- Pathologies of the visual system such as optic atrophy, retinitis or reduced visual acuity.
- Sensorineural deafness.
- Extreme sensitivity to temperature changes.
Other symptoms that are less common, but which can also appear during the course of the disease, are those related to the mental and psychological state of the person. These symptoms can be:
- Aggressive behaviors.
- Personality disorders.
Obsessive Compulsive Disorder.
- Anxiety disorders.
- Affective disorders.
What are the causes?
As mentioned at the beginning of the article, MELAS syndrome is a disease caused by a mutation in mitochondrial DNA. Therefore, it is an inherited disease transmitted through maternal genes.
These alterations occur in a number of specific genes located in the genetic material of mitochondria. Most of these specific genes are responsible for converting oxygen, sugars and fats into energy; while others are involved in the production of tRNA molecules responsible for building amino acid structures.
What is the treatment and prognosis?
For the moment, no specific treatment has been developed for MELAS syndrome, but specific treatments are carried out for each of the symptoms which presents to the patient, as well as a series of palliative care to improve their quality of life.
As part of the usual protocol, a group of specialists including neurologists, cardiologists, ophthalmologists or endocrinologists, among others, is responsible for developing a specialized treatment that adapts to the symptoms and needs of the patient.
Unfortunately, these treatments do not completely relieve the effects of this condition, so the person usually has progressive cognitive impairment, followed by psychomotor problems, decreased hearing and visual abilities, and a whole host of medical complications up to the point. upon the patient’s death.