Metachromatic leukodystrophy (MLD) is one of the genetically conditioned diseases of autosomal recessive inheritance, and is characterized by arylsulphatase A deficiency (ARSA) and the accumulation of metachromatic deposits (sulphatides) in the nervous system and internal organs. As a consequence, defuse demyelinisation in the brain and peripheral nerves take place. There are 4 clinical forms that vary by the age at onset: early infantile form, late infantile form, juvenile form and late-onset form. Reduction of the activity of ARSA is the result of the disorder of the gene placed on the long arm of chromosome 22.13. The disturbances can have the character of mutation, deletion or nonsense mutation. Neurochemical research has enabled the isolation of sulphatase from the insufficiency of ARSA activity, being the result of the insufficiency of several kinds of sulphatase and the consequence of the ARSA protein activator insufficiency. The basic diagnostic criteria are the revealing of the presence of metachromatic deposits or increased content of sulphatides in cells and in systemic fluids, and also proving a significant decrease of ARSA activity in leukocytes (of the culture of fibroblasts and in urine). In the clinical picture, polyneuropathy, muscular weakness, muscle hypotomy, astigmatism, speech impairment of the type dysartia, bulbar signs, optic nerve atrophy, intellectual function impairment and epileptic fits usually are dominant symptoms. There are no known effective treatment methods. One can only hope that therapeutic progress will be achieved in the field of gene therapy. 

metachromatic leukodystrophy, arylsulphatase A, metachromatic deposits – sulphatides