Benign (nonparoxysmal) familial chorea of early onset: an electroneurophysiological examination of two families.

A nonparoxysmal nonprogressive autosomal dominant choreatic disorder of early onset is described in two families. Laboratory investigations of blood, urine and cerebrospinal fluid were normal. Extensive electroneurophysiological examinations did not reveal evident abnormalities. The contingent negative variation was also normal, except for a P500. These electroneurophysiological data are the opposite of what can be found in cases of Huntington's chorea.