Definition 

Leukodystrophy is a rare disease that results in the progressive decline of the myelin, or “white matter,” of the brain. Myelin works to insulate and protect axons, which transmit signals from the brain throughout the body.

Types of leukodystrophies include:

  • Metachromatic leukodystrophy
  • Krabbé disease
  • Adrenoleukodystrophy
  • Adrenomyelopathy
  • Pelizaeus-Merzbacher disease
  • Canavan disease
  • Childhood ataxia with central nervous system hypomyelination (CACH, also called vanishing white matter disease)
  • Alexander disease
  • Refsum disease
  • Cerebrotendinous xanthomatosis

Most leukodystrophies begin in infancy or childhood. However, there are several types that may not begin until adolescence or early adulthood.

Neuronal Axon With Myelin Sheath 

AX00010_97870_1_myelin_sheath

© 2009 Nucleus Medical Media, Inc.

 

Causes 

Leukodystrophy is caused by genetic defects that lead to imperfect growth or development of the myelin sheath that covers the axon. (An axon is a part of the nerve cell.) Each type of leukodystrophy is the result of a certain genetic defect that controls one of the chemicals that make up myelin. Most leukodystrophies are inherited, or passed from parent to child. Others may arise spontaneously.

Risk Factors 

The following factor is thought to increase the risk of leukodystrophy:

  • Family history of the disease

Symptoms 

Symptoms of leukodystrophy may include:

  • Gradual decline of the health of an infant or child who previously appeared well
  • Loss or increase in muscle tone
  • Change in movements
  • Seizures
  • Abnormal eye movements
  • Change in gait
  • Loss of speech
  • Loss of the ability to eat
  • Loss of vision
  • Loss of hearing
  • Change in behavior
  • Slowdown of mental and physical development

Some leukodystrophies are accompanied by involvement of other organ systems, resulting in:

  • Blindness
  • Heart disease
  • Enlargement of the liver and spleen
  • Skeletal abnormalities, such as short stature, coarse facial appearance, and joint stiffness
  • Respiratory disease leading to breathing problems
  • Bronzing of the skin
  • Formation of cholesterol nodules on tendons

Diagnosis 

Your doctor will ask about your symptoms and medical history, and perform a physical exam. She will also perform magnetic resonance imaging (MRI) to produce detailed images of the brain, which can help in the diagnosis of leukodystrophy. Other tests include:

  • Urine analysis
  • Nerve biopsy
  • Blood test
  • Biopsy —removal of a sample of skin tissue
  • CT scan —a type of x-ray that uses a computer to make pictures of structures inside the skull
  • Lumbar puncture —a procedure to collect cerebrospinal fluid
  • Nerve conduction testing —a test that measures the speed and degree of electrical activity in a nerve to determine if it is functioning normally

Treatment 

Talk with your doctor about the best treatment plan for you. Treatment options include:

Management of Symptoms 

Depending on the type of leukodystrophy and the symptoms, treatment may include:

  • Medications
  • Physical, occupational, and/or speech therapy
  • Nutritional programs
  • Education
  • Recreational programs

Bone Marrow Transplant 

In a few of the leukodystrophies, bone marrow transplant may help stop the progression of the disease.

Enzyme Replacement Therapy 

Replacement of the abnormal or absent enzyme is being explored for a few of the leukodystrophies. Research is being done in this area. Talk to your doctor to find out what treatments may be right for you.

Prevention 

There is no known way to prevent leukodystrophy. For parents who have had a child with leukodystrophy, genetic counseling may be beneficial to find out the chances of having another child with the disease.