Brain proton magnetic resonance spectroscopy and neuromuscular pathology in a patient with GM1 gangliosidosis.

The authors report the clinical, neuroradiologic, and neuromuscular pathological findings in a patient with GM1 gangliosidosis. The proton magnetic resonance spectroscopy, previously reported in a single patient with GM1 gangliosidosis, detected a mild reduction of N-acetylaspartate, consistent with relative paucity of axons and neurons and increased levels of myoinositol suggestive of gliotic white matter changes along with the accumulation of an additional compound that could represent either guanidinoacetate or Gal beta 1-6Gal beta 1-4)GlcNAc, an oligosaccharide previously isolated from the urine of GM1 gangliosidosis patients. Although these findings will have to be further confirmed in more patients with GM1 gangliosidosis, they suggest that proton magnetic resonance spectroscopy may provide useful end points to assess the efficacy of novel treatments that could soon become clinically available. Histologically, no significant alterations were found in axons, but there was evidence of redundant and inappropriately folded myelin, which is a feature attributed to disturbed axon-glial interactions.