Joint stiffness in the fingers and knees. Macrocephaly, coarse facial features and limited language skills. Surgical history revealed umbilical and inguinal hernia repairs.
The young boy presented with joint stiffness in the fingers and knees. Further examination disclosed macrocephaly, coarse facial features and limited language skills. Surgical history revealed umbilical and inguinal hernia repairs. MRi of the brain and a radiograph of both hands were performed. The findings were typical of mucopolysaccharidosis. In this case the deficiency of lysosomal iduronate sulfatase and the presence of urinary dermatan sulfate and keratan sulfate were consistent with Hunter syndrome (mucopolysaccharidosis type II, the only X-linked recessive type).
Mucopolysaccharidosis is an inherited lysosomal storage disorder with accumulation of glycosaminoglycans (dermatan sulfate, heparan sulfate) in the liver, spleen, connective tissue, leucocytes, chondrocytes, endocardium, coronary arteries.
In the brain, glycosaminoglycans accumulate in the tissue around vessels, accounting for the cribriform changes in the white matter. Pathologically, these correspond to dilated Virchow-Robin spaces. The perpendicular orientation of the penetrating arterioles into the corpus callosum may explain the typical radiating pattern. The basal ganglia may be involved as well. Chronologically, cribriform changes in the white matter are followed by more diffuse increase in signal intensity of the white matter on T2-weighted MR images, due to demyelination, ischemia and gliosis, and later by atrophy and ventricular enlargement.
Posterior fossa abnormalities like megacisterna magna, Dandy-Walker complex or arachnoid cysts are often associated. Hydrocephalus may occur. The skeletal deformities are termed “dysostosis multiplex” and begin at six months of age. Hand deformities, macrocephaly with J-shaped sella turcica, anteriorly hooked upper lumbar vertebrae are typical. Other features not present in this patient are hepatosplenomegaly, valvular cardiac disease, carpal tunnel syndrome and hearing loss. Most patients also have a history of recurring abdominal hernias.
Differential Diagnosis List