Chromosome 16q22.1‐linked autosomal dominant cerebellar ataxia: An autopsy case report with some new observations on cerebellar pathology

An autopsy case of chromosome 16q22.1‐linked autosomal dominant cerebellar ataxia is reported. The patient was a 77‐year‐old man who died after a clinical course of about 19 years characterized by pure cerebellar ataxia. Main neuropathological findings included moderate loss of Purkinje cells, variegated degenerative features of the remaining Purkinje cells, finely fibrillary material surrounding the perikarya of Purkinje cells, and ubiquitin‐immunoreactive small dots in the molecular layer and cerebellar white matter. Neuritic hyperplasia surrounding the perikarya of Purkinje cells was also a prominent finding. Golgi impregnation study demonstrated poor dendritic arborization of some Purkinje cells. It is our assumption that the pathological processes leading to Purkinje cell death in this disorder are not singular because the intracellular functions of the protein coded by the mutant gene are manifold, and the multiplicity of the pathological processes is reflected in diverse cytomorphological changes seen in degenerating Purkinje cells.