The twitcher mouse: normal pattern of early myelination in the spinal cord.

The pattern of early myelination was investigated in the dorsal columns of the cervical spinal cord in the twitcher, an authentic murine model of human globoid cell leukodystrophy, and their littermates. There were no differences in the number of myelinated fibers until the day 20 postnatal. However, myelin sheath in the homozygous affected twitchers at the day 20 were thinner than those of heterozygous and normal littermates, while at the day 10 no significant differences were detected. These observations indicated that in the twitcher mouse, despite the genetic deficiency of galactosylceramidase, myelination progresses normally in early stages and then hypomyelination becomes apparent before myelin breakdown.