A family with arm atonic variant of paroxysmal kinesigenic choreoathetosisand hypercalcitoninemia

We report a family with an incompletely atonic variant of paroxysmal kinesi genic choreoathetosis (PKC). Three members of the family experienced attack s of muscle weakness which resembled the choreoathetotic attacks that occur in PKC in terms of their kinesigenicity and duration, clarity of conscious ness during the attacks, good therapeutic response to low doses of phenytoi n, and familial transmission, but differed from choreoathetotic attacks in PKC in that they were atonic. All three affected individuals were hypercalc itoninemic.