An immunohistochemical study of Purkinje cells in a case of hereditary cerebellar cortical atrophy.

We report an immunohistochemical study of Purkinje cells located in the molecular layer (ectopic Purkinje cells) and in the Purkinje cell layer (orthotopic Purkinje cells) of a patient who died young and had been diagnosed with hereditary cerebellar cortical atrophy from both clinical and neuropathological findings. All the ectopic and orthotopic Purkinje cells were immunoreactive with an anti-calbindin-D antibody, confirming that these stained cells were Purkinje cells. The perikarya of some ectopic and orthotopic Purkinje cells were stained by an antibody to phosphorylated neurofilament. In contrast, Purkinje cells of three normal controls did not react with this antibody. This finding of an abnormal accumulation of phosphorylated neurofilaments in the perikarya may be due to abnormal phosphorylation. Moreover, the regions around the cell bodies of some ectopic and orthotopic Purkinje cells were intensely immunoreactive with an antibody to synaptophysin, which suggests an abnormal increase in presynaptic terminals. It is suggested that ectopia of Purkinje cells, accumulation of phosphorylated neurofilament in the perikarya and an abnormal increase in presynaptic terminals around the soma of the Purkinje cells may be relevant to the pathophysiology of Purkinje cell degeneration in this case. In addition, the relationship between phosphorylated neurofilament and synaptophysin reactivity is discussed.