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

© 2011 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 likely 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 (or other) 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
• Evoked potential test—a test that measures how well signals are conducted through the nervous system

Treatment

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

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.