A Dutch family with benign hereditary chorea of early onset: differentiation from Huntington's disease.

A large Dutch family of 88 members, running through five generations, is described with benign hereditary chorea of early onset. The clinical presentation was heterogeneous. The chorea manifested in late infancy or childhood, interfered with writing, was non-disabling, stable or even improved in adulthood in most cases, but was slowly progressive with gait impairment in some. There was mild dysarthria and normal intelligence. EEG brain CT-scanning and MRI were normal. Huntington's disease was excluded by analysis of the I T 15 gene, which showed a normal number of the CAG trinucleotide repeats in two patients. It is concluded that benign hereditary chorea of early onset is an entity different from Huntington's disease and that in cases of early onset chorea the diagnostic accuracy is markedly improved by DNA testing.