Benign hereditary chorea--entity or syndrome?
The existence of "benign hereditary chorea" (BHC), a rare disorder of childhood-onset familial chorea without other neurologic features or progression, has increasingly been questioned, because many patients with this disorder were subsequently diagnosed with different conditions. We therefore analyzed all published reports of families with BHC and contacted their authors to obtain follow-up information. In addition, we reviewed all patients in whom at least one of the authors had at some stage considered a possible diagnosis of BHC. Of 42 families reported to have BHC in the literature, we obtained follow-up information on 11 families, three of which had been seen by 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 11 families in the literature, the diagnosis of BHC was changed in nine. In the remaining two families, atypical features suggesting different diagnoses were present in the original reports. In none of our own previously unreported patients (seven familial and four sporadic) was BHC diagnosed unequivocally by all evaluators after review of their video recordings. In three of these families and all four sporadic patients the diagnosis was changed; in one family multifocal myoclonus could not be differentiated from chorea by any author, and in the remaining three families no consensus between the raters was found. Apart from the 11 families in whom we obtained follow-up information, analysis of the remaining 31 reports on families with BHC also revealed atypical features in the majority. We conclude that BHC is not a diagnosis, but a syndrome that requires further investigation. Whether there is a distinct entity "BHC" with a single gene abnormality remains to be proven.