The mucopolysaccharidoses: characterization by cranial MR imaging

Area of Science:

• Neurology
• Radiology
• Genetics

Background:

• Mucopolysaccharidoses (MPS) are a group of inherited metabolic disorders.
• These disorders lead to the accumulation of glycosaminoglycans in various tissues, including the central nervous system.
• Neuropathological changes in MPS can significantly impact cognitive function and overall prognosis.

Purpose of the Study:

• To characterize magnetic resonance (MR) imaging findings in patients with mucopolysaccharidoses (MPS).
• To assist in the diagnosis and categorization of different MPS subtypes.
• To define the role of MR imaging in the preoperative evaluation of MPS patients.

Main Methods:

• Retrospective analysis of routine T1-weighted and T2-weighted MR images at 1.5 T.
• Study included children with Hurler syndrome (MPS IH), Hunter syndrome (MPS II), and Sanfilippo A syndrome (MPS IIIA).
• MR findings were graded to assess severity and patterns of brain involvement.

Main Results:

• Hallmark cribriform changes (sieve-like or multicystic) were observed in the white matter, corpus callosum, and basal ganglia in all MPS subtypes.
• Cerebellum and brain stem were not affected by cribriform changes.
• Severe cribriform changes correlated with somatic involvement but inversely with atrophy and ventricular enlargement; mental retardation was most severe in Hurler syndrome.

Conclusions:

• A natural course of MPS brain changes is postulated: cribriform changes first, followed by white matter changes, and finally atrophy.
• More severe cribriform changes and corpus callosum involvement suggest a poorer prognosis.
• MR imaging can identify and grade these changes, potentially guiding optimal therapeutic intervention before significant atrophy occurs.