Cerebral manifestations of mucopolysaccharidoses

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The mucopolysaccharidoses (MPSs), which constitute a hereditary subgroup of the lysosomal storage disorders, have distinctive cerebral manifestations.

The MPSs are characterized by excessive accumulation of mucopolysaccharides secondary to deficiencies in specific enzymes (lysosomal hydrolases) responsible for degradation of mucopolysaccharides (also known as glycosaminoglycans).

For a general discussion of the underlying condition, please refer to the article mucopolysaccharidoses.

Their characteristic neuroimaging features are best appreciated on MRI:

  • perivascular (Virchow-Robin) spaces dilatation is usually seen within the periventricular white matter, corpus callosum, basal ganglia, subcortical white matter, thalami or brainstem. The spaces usually have a radial orientation from the subependymal region toward the cortex .
  • white matter lesions are one of the most common findings in MPS. They appear as focal or confluent areas of T2-FLAIR hyperintensity, sometimes lesions coalesce and become large simulating leukodystrophy. Lesions usually occur within the periventricular white matter but it can also occur in the subcortical white matter. Lesions frequently start at the peritrigonal regions.
  • hydrocephalus is usually communicating type which is slowly progressive and typically manifests as ventricular and subarachnoid space dilatation
  • brain atrophy is a common finding in patients with MPS
  • cervical spinal canal stenosis usually occurs at the level of the atlantoaxial joint. It also can occur in the thoracic and/or lumbar spine. Dysplastic odontoid process associated with surrounding soft-tissue thickening are also common findings.
  • skull abnormalities include thickening of the diploe, skull base abnormalities (such as the J-shaped sella), and macrocephaly
  • spine manifestations include wedge-shaped vertebrae, platyspondyly, anterior beaking and posterior scalloping (bullet-shaped vertebrae), wide disc spaces, scoliosis and thoracolumbar kyphosis (or gibbus deformity)