Hypoyelination in I-cell disease; MRI, MR spectroscopy and neuropathological correlation

MRI of a female patient with genetically diagnosed I-cell disease at 2 weeks, 4 and 8 months revealed delayed myelination or hypomyelination with decreased choline on MR spectroscopy. Brain autopsy was performed 2 h after death at 14-month-old. Immunoreactivities for myelin basic protein and proteolipid proteins, markers for mature myelin sheath, were reduced in the myelinated fibers and oligodendrocytes in the white matter, indicating the hypomyelination in the central nervous system. I-Cell disease should be added to the list of delayed or hypomyelination conditions, and this neuroimaging finding could be a key for differentiating I-cell disease from the clinically similar disorder of Hurler syndrome characterized by perivascular lacunation.