Benign hereditary chorea 2: Pathological findings in an autopsy case

Two Japanese families with benign hereditary chorea (BHC) 2 have recently been reported. BHC 2 is characterized by adult‐onset non‐progressive chorea, and by genetic abnormality in the locus of chromosome 8q21.3‐q23.3. This differs from the genetic abnormality previously reported in BHC. Here we report the first autopsied case of a member of one of two known families with BHC 2. A normally developed woman recognized choreiform movements of her bilateral upper extremities beginning approximately at age 40. The movements had slowly spread to her trunk and lower extremities by approximately age 60. Generalized muscular hypotonia was also observed. The symptoms persisted until her death at the age 83, but had not worsened. Neuropathological examination revealed mild to moderate neuronal loss and astrocytosis in the striatum and decreased volume of cerebral white matter with astrocytosis bilaterally. Additionally, sparse but widely distributed neurofibrillary tangles and argyrophilic threads as well as scattered tufted astrocytes immunoreactive for 4‐repeat isoform of tau were observed in the cerebrum, brainstem and cerebellum, showing 4‐repeat tauopathy similar to that of progressive supranuclear palsy (PSP). Unique neuronal cytoplasmic inclusions were observed in the oculomotor nuclei; however, any specific immunoreactivities (e.g. ubiquitin and p62) were not detected, suggesting the presence of previously undescribed protein intracellular inclusions. Clinicopathologically, chorea accompanied with generalized muscular hypotonia seemed to be associated with mild degeneration of the striatum and cerebral white matter. The significance of PSP‐like changes in the pathogenesis of BHC 2 remains to be elucidated.