Benign Hereditary Chorea: Clinical, Neuroimaging, and Genetic Findings

Benign hereditary chorea is an autosomal dominant disease with an early onset of symptoms. In some families, symptoms tend to decrease in adulthood, suggesting that the disorder results from a developmental disturbance in the brain. Individuals with benign hereditary chorea, a nonprogressive disease, have normal or slightly below normal intelligence. The locus for benign hereditary chorea is on chromosome 14. Benign hereditary chorea is a result of mutations in the thyroid transcription factor 1 gene. Previous neuroimaging and pathological investigations of the brain showed no notable abnormalities in patients with this condition. In this study, 5 patients from 1 family with typical clinical features of benign hereditary chorea are presented. Clinical severity varied considerably in the family. Brain magnetic resonance imaging results were normal. Brain single photon emission computed tomography in 3 children, performed 1 hour after intravenous injection of 0.35 mCi/kg of body weight of technetium 99m ethyl cysteinate dimer, showed markedly decreased uptake in the right striatum and the right thalamus in 1 child. The oldest child had mildly reduced uptake in the right putamen and the left thalamus. Brain single photon emission computed tomographic findings in the youngest child were normal. Contrary to other reports of radionuclide brain imaging, notable brain single photon emission computed tomography changes were detected in 2 of 5 patients. Brain single photon emission computed tomography findings did not seem to correlate with the clinical status of the children.