Reduced Purkinje cell density in Huntington's disease.

We studied, in a "blind" and quantitative fashion, the density of cerebellar Purkinje cells in 17 adult cases of Huntington's disease (HD), 17 patients with other movement disorders, 17 with schizophrenia, and 23 normal controls. There was a highly significant reduction in Purkinje cell density in HD compared with any of the other three groups. A much smaller difference in neuronal density between patients with other movement disorders and normal controls was barely significant. Eight of the 17 HD patients and only 1 of the other 57 subjects had Purkinje cell density less than 50% of the mean for the normal controls. The low density of Purkinje cells in HD could not be attributed to aging, seizures, or cause of death, nor was it merely a part of a generalized brain atrophy. The loss of large Purkinje cells suggests that the neuronal loss in HD may not be restricted to small and medium-size neurons.