Mucopolysaccharidoses are a group of metabolic lysosomal storage diseases caused by the absence or impaired function of lysosomal enzymes required for glycosaminoglycan metabolism. As a result, glycosaminoglycans accumulate in the cells, causing cellular damage which affects the function of multiple organs and, in most cases, leads to mental retardation
Mucopolysaccharidosis IV (MPS IV, Morquio syndrome) is categorized into two subtypes by means of the enzyme deficiency underlying the disease, namely, either galactose 6-sulfate sulfatase (GALNS, Type A) or beta-galactosidase (GLB1, Type B), both of which are required for metabolism of keratan sulfate sugar chains.
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