The current study will evaluate the safety and efficacy of T2000 in patients with M-D. Patients will receive doses of T2000 beginning at 200 mg a day and increasing every other week by an additional 200 mg a day up to a maximal dose of 1000 mg a day. The total duration of treatment will be 12 weeks. Patient's symptoms of myoclonus and dystonia, as well as overall neurological examination, will be monitored throughout the study. The response to T2000 will be determined by comparing the severity of myoclonus and dystonia while patients are receiving T2000 compared to the symptoms observed without active medication.