Autosomal dominant chorea-acanthocytosis with polyglutamine-containing neuronal inclusions

Background: The term chorea-acanthocytosis describes a heterogeneous group of neurodegenerative disorders with variable clinical features and modes of inheritance. The characteristic acanthocytic appearance of red blood cells is attributed to abnormalities of a membrane protein, band 3, although the relationship between this and the neurodegenerative process has yet to be determined. Objective: To describe features of phenotype, inheritance, and neuropathological findings in a family with this disorder. Methods: Clinical and hematologic evaluations were performed on all available family members and neuropathological examination was performed on one case. Results: Autosomal dominant inheritance was evident, with variable clinical features of chorea or parkinsonism, marked cognitive changes, but no seizures or peripheral neurologic abnormalities. Abnormalities of band 3 were demonstrated on gel electrophoresis of red blood cell membranes. Neuropathological examination revealed severe neuronal loss of the caudate-putamen and intranuclear inclusion bodies in many areas of the cerebral cortex. These inclusion bodies were immunoreactive for ubiquitin, expanded polyglutamine repeats, and torsinA. Conclusions: This family extends the genetic spectrum of chorea-acanthocytosis to include autosomal dominant inheritance, possibly due to expanded trinucleotide repeats. Intraneuronal inclusion bodies have recently been associated with a wide range of inherited neurodegenerative disorders and may provide a clue to etiopathogenesis, in addition to potentially indicating a function of torsinA.