GENE LOCUS FPD1 OF THE DYSTONIC MOUNT-REBACK TYPE OF AUTOSOMAL-DOMINANT PAROXYSMAL CHOREOATHETOSIS

Genes for paroxysmal choreoathetosis have been localized to chromosome s Ip and 2q. We have reinvestigated one of the classic large autosomal -dominant pedigrees of the dystonic Mount-Reback type of paroxysmal ch oreoathetosis 20 years after its first assessment. These patients pref er diazepam for both prevention and treatment of attacks and did not d evelop addiction on an intermittent regime. Migraine occurred in a thi rd of the patients. Genetic data localized the underlying mutation to the FPD1 locus (familial paroxysmal dyskinesia type ii on chromosome 2 q and support locus homogeneity fur the Mount-Reback syndrome. The dat a also refine the FPD1 candidate region to 3.6 cM between the markers D2S164 and D2S2359, which may facilitate the investigation of the role of the candidate ion channel gene SLC2C.