AbstractA case of familial paroxysmal dystonic choreoathetosis (PDC) documented by video/EEG monitoring is described. The father of the proband is affected by exertional cramping but not PDC, lending support to the previous hypothesis that exertional cramping may represent a “forme fruste” or the incomplete expression of PDC. Other family members affected by PDC are women, with exercise‐induced cramping alone found in two men. Two of the women report prolonged exertion as a precipitant of lengthy spells consistent with typical PDC rather than the previously described “intermediate,” exercise‐induced form of PDC. Exertional cramping in families affected by PDC may represent the variable expression of the “dystonia gene” in male members. Conversely, exercise‐induced PDC, both of the intermediate and longer form described here, may have a predilection to manifest in women.