Benign hereditary chorea - Entity or syndrome?

The existence of "benign hereditary chorea" (BHC), a rare disorder of child hood-onset familial chorea without other neurologic features or progression , has increasingly been questioned, because many patients with this disorde r were subsequently diagnosed with different conditions. We therefore analy zed all published reports of families with BHC and contacted their authors to obtain follow-up information. In addition, we reviewed all patients in w hom at least one of the authors had at some stage considered a possible dia gnosis of BHC. Of 42 families reported to have BHC in the literature, we ob tained follow-up information on ii families, three of which had been seen b y us. An additional seven new, unreported families and four sporadic cases, in which this diagnosis was suspected by at least one of us at one point, were reviewed and videotaped. On reviewing the videotapes of the II familie s in the Literature, the diagnosis of BHC was changed in nine. In the remai ning two families, atypical features suggesting different diagnoses were pr esent in the original reports. In none of our own previously unreported pat ients (seven familial and four sporadic) was BHC diagnosed unequivocally by all evaluators after review of their video recordings. In three of these f amilies and all four sporadic patients the diagnosis was changed; in one fa mily multifocal myoclonus could, not be differentiated from chorea by any a uthor, and in the remaining three families no consensus between the raters was found. Apart from the II families in whom we obtained follow-up informa tion, analysis of the remaining 31 reports on families with BHC also reveal ed atypical features in the majority. We conclude that BHC is not a diagnos is, but a syndrome that requires further investigation. Whether there is a distinct entity "BHC" with a single gene abnormality remains to be proven.