The Diagnosis of Morquio Disease Correlating the Clinical, Radiological and Biochemical Findings: A Case Series

InTRoDuCTIon Mucopolysaccharidoses (MPS) are a group of inherited storage diseases which are caused due to the deficiency of lysosomal enzymes which are needed to degrade glycosaminoglycans (GAGs). GAGs are the polymers of a disaccharide unit which are composed generally of uronic acid and sulphated amino or N-acetylated monosacchrides. GAGs are linked to proteins to form proteoglycans, which are the major constituents of the connective tissue as well as the nuclear membranes. The degradation of the proteoglycans starts with the proteolytic removal of the proteins, followed by the stepwise degradation of the GAG moiety. The failure to degrade due to an absent or a grossly reduced activity of the mutated lysosomal enzymes results in the intra-lysosomal accumulation of GAG. The distended lysosomes accumulate in the cell and interfere with the cellular functions. This leads to a characteristic pattern of clinical, radiological and biochemical abnormalities.