Myelin, which lends its color to white matter in the brain, is a complex substance made up of at least 10 different chemicals.
It refers to the progressive degeneration of the white matter of the brain due to imperfect growth or abnormal development of the myelin sheath , that is, the fat covering that acts as an insulator around the nerve fiber.
For this reason, leukodystrophy represents a group of disorders that are caused by genetic defects in the way myelin produces or metabolizes these chemicals.
Various leukodystrophies can appear because they are the result of a defect in the gene that controls one of the chemicals.
Experts currently know about 52 different types, but the specific and most common leukodystrophies are:
- Leucodistrofia metacromática.
- Krabbé disease.
- Pelizaeus-Merzbacher disease.
- Canavan disease.
- Infantile ataxia with hypomyelination of the central nervous system, also known as white matter disease.
- Alexander disease.
- Refsum’s disease.
- Cerebrotendinous xanthomatosis.
In conclusion, leukodystrophy is not just a disease; are a group of diseases that affect the central nervous system .
Most leukodystrophies are passed down from the parents, because they are found in the genes. Sometimes symptoms will appear early in childhood.
But because the diseases are progressive, meaning they get worse over time, some children born with a form of leukodystrophy may appear to be in stable and healthy health and develop this condition over the years.
Symptoms of leukodystrophy
The most common symptom of a leukodystrophy disease is a gradual decline in a previously well-seen baby or child.
Progressive loss can appear as follows:
- Deficiency in body tone.
- Weak and inaccurate movements.
- Impaired gait.
- Difficulty speaking and modulating correctly.
- Eating problems
- Impaired vision, hearing, and behavior.
- There is often a slowdown in mental and physical development.
Symptoms vary depending on the specific type of leukodystrophy and can be difficult to recognize in the early stages of the disease.
The one thing that all leukodystrophies have in common is that they cause abnormal development or destruction of the brain’s myelin sheath. Without it, the nervous system cannot function properly.
Additionally, each leukodystrophy affects it differently. Other factors of the organism and development of the individual are also involved, such as:
- Balance and mobility problems.
- Difficulty in learning.
- Bladder problems
- Breathing difficulties.
- Developmental delays.
- Muscle control disorders.
For example, one type of leukodystrophy is Canavan disease and it generates the following problems in the affected person:
- Decreased muscle tone, especially in the neck and deformed legs, for example very straight and flexed arms.
- Difficulty to focus, until reaching a deterioration without return of the sight and finally the blindness.
- Sporadic seizures that become frequent over time.
- Sometimes symptoms appear shortly after the birth of a child, and sometimes into adulthood.
The signs of Refsum Disease, for example, usually occur around the age of 20, but can go as long as 50 years. Some of the common symptoms include:
- Degeneration of the retina in the eye.
- Loss of the sense of smell.
Although each leukodystrophy is different, unfortunately the health of the affected individual or child is seriously compromised to the point of gradually worsening by some factor regardless of the fact that after birth the development seems to be going perfectly.
There have even been cases where hearing, speech, the ability to eat, behavior or thinking are so affected that the affected person can no longer perform assignments or activities on their own.
Most leukodystrophies are inherited, which means they are passed down through family genes.
Some may not be inherited, but are still caused by a genetic mutation. One child in your family may have leukodystrophy, and others may not.
For example, Alexander’s disease does not appear to be inherited genetically, so the child may have a defective gene even if the mother or partner does not have it or has it.
People or parents who have a child with leukodystrophy and are planning to have more children, may need to consider that decision or seek genetic counseling, to anticipate that the next family member will have the same condition.
Diagnosis of leukodystrophy
The diagnosis of leukodystrophy can be difficult. Doctors often have to use several types of tests, including:
- Blood and urine tests.
- Computed tomography.
- Genetic testing.
- Magnetic resonance imaging.
- Psychological and cognitive tests.
Treatment for most leukodystrophies is symptomatic and supportive, and may include:
- Physical, occupational and speech therapies.
Also to achieve a quality of life for the patient or affected, the following are recommended:
- Nutritional programs.
- Educational programs.
- Recreational programs.
According to some specialist doctors in the area, bone marrow transplantation is recommended as a promising treatment for some of the leukodystrophies because there is no cure for most types of this condition.
Scientists are also investigating whether replacing certain enzymes can help treat some types of leukodystrophy.