Metachromatic leukodystrophy is an inherited disorder characterized by the accumulation of fats called sulfatides in cells. This accumulation especially affects cells in the nervous system that produce myelin, the substance that insulates and protects nerves. Nerve cells covered by myelin make up a tissue called white matter. Sulfatide accumulation in myelin-producing cells causes progressive destruction of white matter (leukodystrophy) throughout the nervous system.
Causes: Metachromatic leukodystrophy (MLD) 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.
Diagnosis: Tests that may be done 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 signalling studies, Urinalysis, Urine chemistry.
Treatment: 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.
We have calculated the relative frequency and the birth prevalence of lysosomal storage diseases (LSDs) in The Netherlands based on all 963 enzymatically confirmed cases diagnosed during the period 1970-1996. The combined birth prevalence for all LSDs is 14 per 100,000 live births. Glycogenosis type II is the most frequent LSD with a birth prevalence of 2.0 per 100,000 live births, representing 17% of all diagnosed cases.