[Improvement of action myoclonus in a patient with dentatorubral-pallidoluysian atrophy by piracetam].

We report a 13-year-old girl with dentatorubal-pallidoluysian atrophy (DRPLA), presenting clinically as progressive myoclonic epilepsy. The action myoclonus, which severely impaired her daily life, was markedly improved by administration of piracetam, a drug reportedly useful for myoclonus of cortical origin. In our case, piracetam effectively suppressed severe subcortical myoclonus of DRPLA, suggesting that the drug may be useful in the treatment of both cortical, and subcortical myoclonus.