Metachromatic leukodystrophy (MLD) is one of a group of genetic disorders called the leukodystrophies. These diseases impair the growth or development of the myelin sheath, the fatty covering that acts as an insulator around nerve fibers. Myelin, which lends its color to the white matter of the brain, is a complex substance made up of a mixture of fats and proteins. Some leukodystrophies are caused by genetic defects of enzymes that regulate the metabolism of fats needed in myelin synthesis. MLD is cause by a deficiency of the enzyme arylsulfatase A. MLD is one of several lipid storage diseases, which result in the toxic buildup of abnormal fatty materials (lipids), which interfere with the normal fats and proteins in the myelin sheath. There are three forms of MLD: late infantile, juvenile, and adult. Onset of the late infantile form (the most common MLD) is typically between 12 and 20 months following birth. Affected children have difficulty walking after the first year of life. Symptoms include muscle wasting and weakness, muscle rigidity, developmental delays, progressive loss of vision leading to blindness, convulsions, impaired swallowing, paralysis, and dementia. Children may become comatose. Most children with this form of MLD die by age 5. The juvenile form of MLD (between 3-10 years of age) usually begins with impaired school performance, mental deterioration, and dementia and then develop symptoms similar to the infantile form but with slower progression. The adult form commonly begins after age 16 as a psychiatric disorder or progressive dementia. Symptoms include impaired concentration, ataxia, seizures, dementia, and tremor..
The National Institute of Neurological Disorders and Stroke (NINDS), a part of the National Institutes of Health (NIH), conducts
research on the lipid storage diseases in laboratories at the NIH and also supports additional research through grants to
major medical institutions across the country.
A combination of gene therapy and transplantation of the patient's own bone marrow cells is currently ongoing in Europe and
being discussed the the U.S. Food and Drug Administration in the United States. A trial of Arylysulfatase A has been completed in late infantile MLD in the United States and results are not yet published.
The Arc of the United States 1825 K Street, NW Suite 1200 Washington, DC 20006 Info@thearc.org http://www.thearc.org Tel: 202-534-3700 800-433-5255 Fax: 202-534-3731 |
Myelin Project P.O. Box 39 Pacific Palisades, CA 90272 info@myelin.org http://www.myelin.org Tel: 800-869-3546 310-459-1071 Fax: 310-230-4298 |
National Organization for Rare Disorders (NORD) 55 Kenosia Avenue Danbury, CT 06810 orphan@rarediseases.org http://www.rarediseases.org Tel: 203-744-0100 Voice Mail 800-999-NORD (6673) Fax: 203-798-2291 |
National Tay-Sachs and Allied Diseases Association 2001 Beacon Street Suite 204 Boston, MA 02135 info@ntsad.org http://www.ntsad.org Tel: 800-90-NTSAD (906-8723) Fax: 617-277-0134 |
United Leukodystrophy Foundation 2304 Highland Drive Sycamore, IL 60178 office@ulf.org http://www.ulf.org Tel: 815-895-3211 800-728-5483 Fax: 815-895-2432 |
MLD Foundation 21345 Miles Drive West Linn, OR 97068 info@MLDFoundation.org http://www.mldfoundation.org Tel: 800-617-8387 503-656-4808 |
Prepared by:
Office of Communications and Public Liaison
National Institute of Neurological Disorders and Stroke
National Institutes of Health
Bethesda, MD 20892
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Last updated October 22, 2012