Globoid cell leucodystrophy in polled Dorset sheep.

Globoid cell leucodystrophy (Krabbe's disease) was diagnosed in two Polled Dorset sheep from a stud farm. Clinical signs were hind limb incoordination progressing to tetraplegia. Histologic changes in white matter of the brain were myelin destruction, loss of oligodendroglia, astrogliosis and accumulation of distinctive periodic acid-Schiff (PAS)-positive globoid cells. The activities of galactocerebroside beta-galactosidase, the lysosmal enzyme specifically deficient in globoid leucodystrophy, and of three other glycosidase enzymes were compared in brain tissue of one affected and six unaffected sheep. Activities of the three nonspecific glycosidases were similar in all seven brains. Galactocerebrosidase activity was similar in the six control sheep, but in the affected brain was less than 6% of the control mean.