What is Metachromatic Leukodystrophy?
Metachromatic leukodystrophy is a topic we will explain today. This is another topic from Childrean Health Category. After Erythrophobia, Anuptaphobia and Gamophobia, as disorders which start in early childhood, we have decided to write about something far more serious in this article – a metachromatic leukodystrophy.
Metachromatic leukodystrophy (MLD) is a rare, genetic, degenerative disease, a neurometabolic disorder that affects one of 40,000 children in the world. Metachromatic leukodystrophy often caused by the gene mutation; lack or deficiency of the “arylsulfatase A” enzyme in the body. This enzyme is necessary for decommissioning and cleaning of cells from sulfatides. In the white substance of the brain and myelin sheath of peripheral nerves cerebrosides-sulfatides accumulate.
What are Metachromatic Leukodystrophy Symptoms?
Metachromatic leukodystrophy symptoms are:
- Irritability (excessive response to ordinary stimuli; sound, smell, light, heat, cold) the term refers to the children who due to illness are nervous, agitated for no apparent reason
- Difficulty in feeding, dysphagia (not dysphasia, which is a different term)
- Difficulty walking, clumsiness
- Loss of muscle control
- Difficulty in speech, slurred speech
- Hypotonia (decreased muscle tone)
- An abnormally high muscle tone
- Abnormal muscle movements
- Ataxia (loss of ability to coordinate muscular movement)
- Quadriplegia (paralysis from the neck down)
- Esotropia (strabismus)
- Nystagmus (a type of abnormal eye movement)
- Atrophy of the optic nerve
- Behavior problems (avoidant personality disorder, obsessive compulsive personality disorder)
- Psychomotor regression
- Reduced mental function
- Inability to perform normal activities
- Changes in the susceptibility of skin which grows and spreads to the arms and
- Non-epileptic attacks, but attacks muscle tension that cause twisting of the body, head, arms and legs
These are metachromatic leukodystrophy symptoms.
Metachromatic Leukodystrophy Types and Treatment
There are four types of metachromatic leukodystrophy:
Late Infantile Form
After a period of seemingly normal child growth and development, skills such as walking and speech may worsen. Ill children have difficulty walking after the first year, usually around 15-24 months old. Symptoms include irritability, muscle wasting and weakness, progressive loss of vision leading to blindness, swallowing disorders, paralysis and dementia. When clinical symptoms become noticeable, they often appear quickly and rapidly progress and in a short period change with the stabilization period until the next time a symptoms are activated.
The child eventually becomes bedridden, unable to speak, cannot swallow, and with labored breathing. Attacks can occur which gradually disappear over time, cramps are common and very painful, the child is still able to laugh, but in the end they become blind and do not react to the environment. Swallowing becomes difficult and the tube feeding becomes necessary. There is no medication, most children with this form of metachromatic leukodystrophy die by their fifth year, often much earlier. Death usually occurs as a result of infections, such as pneumonia (pneumonia), and not from the metachromatic leukodystrophy.
Early Juvenile Form
It occurs in children aged 4-6 years, motor-functions are lost, and there is a problem with child behavior, irritability. Inability to walk, there is dysarthria (difficulty speaking) and pain in the extremities due to the involvement of peripheral nerves.
This form has a slower progression and is identified by ataxia (it is a loss of ability to control all or some willing muscle movement, perturbation of balance or coordination of movements) and mental deficit. This leukodystrophy life expectancy is 10 years from the start of symptoms.
Late Juvenile Form
The beginning of this metachromatic leukodystrophy type is between 6-12 years of life, and symptoms may become clear during the early school years, where a motor disorder and decline in cognitive function can indicate the onset of disease. Symptoms can include incontinence, difficulty walking, slurred speech.
This form of MLD is often shown as a change of personality and behavioral changes, deterioration of the ability to learn and work. Tremors may occur, muscle shaking and at the end eventually the loss of ability to walk. This leukodystrophy life expectancy is adulthood.
Initial symptoms can occur in 14th year and continue to occur up to 50 years of life as personality changes, deterioration of the ability to deal with any kind of work, as an early dementia with symptoms of psychosis. Initial indications are personality changes, lack of work skills and emotional liability. Most common diagnoses are psychiatric disorders such are as schizophrenia, depression and a person is actually suffering from metachromatic leukodystrophy. Also, a drugs and alcohol abuse may occur. This form progresses slowly, and death may be a few decades after the discovery of symptoms.
Since the cause of metachromatic leukodystrophy is an enzyme deficiency of arylsulfatase A (ARSA), a blood test which shows low levels of the enzyme indicates the symptoms of metachromatic leukodystrophy. Also, there are tests like: MRI (magnetic resonance imaging), CT scan (scanner), DNA testing for ARSA gene and nerve biopsy-nerve conduction velocity (Electroneurography).
At this time there is no cure for metachromatic leukodystrophy. The only treatments are transplantation of bone marrow or stem cells and they are the most effective in slowing or stopping the disease in people who are at an early stage of the disease, i.e. the pre-symptomatic phase. That is why is very important an early diagnosis of this disease. There is no effective causal treatment. Treatment is metachromatic leukodystrophy symptomatic.