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 at least 10 different enzymes. The leukodystrophies are caused by genetic defects in how myelin produces or metabolizes these enzymes. Each of the leukodystrophies is the result of a defect in the gene that controls one (and only one) of the enzymes. MLD is caused by a deficiency of the enzyme arylsulfatase A. MLD is one of several lipid storage diseases, which result in the toxic buildup of fatty materials (lipids) in cells in the nervous system, liver, and kidneys. There are three forms of MLD: late infantile, juvenile, and adult. In the late infantile form, which is the most common MLD, 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. Children with the juvenile form of MLD (between 3-10 years of age) usually begin 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. Adult-onset MLD progresses more slowly than the infantile form.
The Arc of the United States 1010 Wayne Avenue Suite 650 Silver Spring, MD 20910 Info@thearc.org http://www.thearc.org Tel: 301-565-3842 Fax: 301-565-3843 or -5342 |
Myelin Project 1400 Wallace Blvd. Suite 258 Amarillo, TX 79106 candace.root@myelin.org http://www.myelin.org Tel: 806-356-4693 800-869-3546 Fax: 806-356-4694 |
National Organization for Rare Disorders (NORD) P.O. Box 1968 (55 Kenosia Avenue) Danbury, CT 06813-1968 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 Brighton, MA 02135 info@ntsad.org http://www.ntsad.org Tel: 617-277-4463 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 |
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Last updated February 13, 2007