FAMILIAL PAROXYSMAL DYSTONIC CHOREOATHETOSIS REVISITED

A case of familial paroxysmal dystonic choreoathetosis (PDC) documente d by video/EEG monitoring is described. The father of the proband is a ffected by exertional cramping but not PDC, lending support to the pre vious hypothesis that exertional cramping may represent a ''forme frus te'' or the incomplete expression of PDC. Other family members affecte d by PDC are women, with exercise-induced cramping alone found in two men. Two of the women report prolonged exertion as a precipitant of le ngthy spells consistent with typical PDC rather than the previously de scribed ''intermediate,'' exercise-induced form of PDC. Exertional cra mping in families affected by PDC may represent the variable expressio n of the ''dystonia gene'' in male members. Conversely, exercise-induc ed PDC, both of the intermediate and longer form described here, may h ave a predilection to manifest in women.