Dysostosis in mucopolysaccharidosis type 2: A case of longitudinal follow up and literature review

Mucopolysaccharidosis type 2 is a congenital lysosomal disease characterized by iduronate-2-sulfatase deficiency, which leads to excessive accumulation of glycosaminoglycans in tissue. Dysostosis, which primarily involves decreased bone mineralization with morphological changes in the bone, is a major skeletal condition in mucopolysaccharidosis, but its pathophysiology is not well known. Here, we report a case of mucopolysaccharidosis type 2 diagnosed at the age of 2 years with longitudinal follow-up data for more than 15 years. Although the patient underwent bone marrow transplantation, the developmental quotient did not improve, and cranial hyperostosis progressed prominently with a faintly dilated perivascular space. Other dysostoses and contraction of the joints were observed but did not improve either.