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Metachromatic leukodystrophy (MLD) is a genetic disorder that affects nerves, muscles, other organs, and behavior. It slowly gets worse over time.
Alternative NamesMLD; Arylsulfatase A deficiency; Leukodystrophy - metachromatic
Causes, incidence, and risk factorsMLD is usually caused by the lack of an important enzyme called arylsulfatase A. Because this enzyme is missing, chemicals called sulfatides build up in and damage the nervous system, kidneys, gallbladder, and other organs. In particular, the chemicals damage the protective sheaths that surround nerve cells.
The disease is passed down through families (inherited). You must get a copy of the defective gene from both your parents to have the disease. Parents can each have the defective gene, but not have MLD. A person with one defective gene is called a "carrier."
Children who inherit only one defective gene from one parent will be a carrier, but usually will not develop MLD. When two carriers have a child, there is a 25% chance that the child will get both genes and have MLD.
MLD occurs in about 1 in 40,000 people. There are three forms of the disease. They are based on when the symptoms begin:
- Late infantile MLD symptoms usually begin by ages 1 - 2.
- Juvenile MLD symptoms usually begin between ages 4 and 12.
- Adult (and late-stage juvenile MLD) symptoms may occur between age 14 and adulthood (over age 16), but may begin as late as the 40s or 50s.
- Abnormal high muscle tone, abnormal muscle movements
- Behavior problems
- Decreased mental function
- Decreased muscle tone
- Difficulty walking
- Feeding difficulties
- Frequent falls
- Inability to perform normal tasks
- Incontinence
- Irritability
- Loss of muscle control
- Nerve function problems
- Personality changes
- Poor school performance
- Seizures
- Speech difficulties, slurring
- Swallowing difficulty
Signs include:
- Abnormal eye movements
- Abnormal posture
- Decreased or no deep tendon reflexes
- Coma
- Optic nerve atrophy
Possible tests include:
- Blood or skin culture to look for low arylsulfatase A activity
- Blood test to look for low arylsulfatase A enzyme levels
- CT scan
- DNA testing for the ARSA gene
- MRI
- Nerve biopsy
- Nerve velocity conduction studies
- Urinalysis
- Urine chemistry
There is no cure for MLD. Care focuses on treating the symptoms and preserving the patient's quality of life with physical and occupational therapy.
Research is studying techniques to replace the missing enzyme (arylsulfatase A).
Support GroupsFor additional information and resources, see:
- United Leukodystrophy Association - www.ulf.org
- MLD Foundation - www.mldfoundation.org
MLD is a severe disease that gets worse over time. Eventually people lose all muscle and mental function. Life span varies depending on what age the condition started, but the disease course usually runs 3 - 20 or more years.
People with this disorder are expected to have a shorter-than-normal lifespan. The earlier the age at diagnosis, the more quickly the disease progresses.
PreventionGenetic counseling is recommended if you have a family history of this disorder.
What else can I help you with?
What are the characteristics of the juvenile form of metachromatic leukodystrophy?
The juvenile form of metachromatic leukodystrophy is characterized by gait disturbances, urinary incontinence, mental deterioration, and emotional difficulties
What is metachromatic leukodystrophy?
Metachromatic leukodystrophy (MLD) is a rare degenerative neurological disease affecting the fatty covering that acts as an insulator around nerve fibers known as the myelin sheath.
What do people with Metachromatic Leukodystrophy die from?
Liver and kidney falure.
What are the characteristics of adult metachromatic leukodystrophy?
Adult metachromatic leukodystrophy is characterized by emotional disturbances and psychiatric symptoms. Disorders of movement and posture appear later. Dementia and decreased visual function also occur.
What kind of inherited condition is Metachromatic leukodystrophy?
Metachromatic leukodystrophy (MLD), also called sulfatide lipidosis and arylsulfatase A (ARSA) deficiency, is inherited as an autosomal recessive trait, due to mutations in the arylsulfatase A (ARSA) gene
Whatv types of Leukodystrophy are seen in certain ethnic groups?
Canavan disease in Ashkenazi Jews, or globoid cell leukodystrophy (GLD) and metachromatic leukodystrophy (MLD) in Scandinavians.
What is the prognosis for children with the late infantile form of metachromatic leukodystrophy?
Death usually results within five years after the onset of clinical symptoms
What are the possible effects of metachromatic leukodystrophy?
Metachromatic leukodystrophy is a rare genetic disorder that affects the central nervous system, leading to the breakdown of myelin. Symptoms may include muscle weakness, cognitive decline, and vision and hearing loss. Without treatment, it can result in severe disability and premature death.
What rehabilitation do metachromatic leukodystrophy patients undergo?
Physical therapists, occupational therapists, orthopedists, ophthalmologists, and neuropsychologists are often involved in helping maintain optimal function for as long as possible.
What are the symptoms of infantile metachromatic leukodystrophy?
The infant displays irritability and an unstable walk. As the disease progresses, physical and mental deterioration occur and muscle wasting eventually gives way to spastic movements
What is the treatment for metachromatic leukodystrophy?
In infants neurocognitive function may be stabilized, while persons with the juvenile and adult forms of MLD and with mild symptoms are more likely to be stabilized with bone marrow transplantation
How does metachromatic leukodystrophy affect a human organism?
Sulfatide accumulates in the brain and other areas of the body such as the liver, gall bladder, kidneys, and/or spleen. The buildup of sulfatide in the central nervous system causes demyelination
