EFFICACY OF LAMOTRIGINE IN DISABLING MYOCLONUS IN A PATIENT WITH AN mtDNA A3243G MUTATION

Abstract

Mitochondrial disorders may be associated with symptomatic myoclonus. Myoclonus is a cardinal feature of the progressive myoclonus epilepsy syndromes (PMEs), recognized causes of which are the mitochondrial disorders myoclonic epilepsy with ragged red fibers (MERRF) and mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episodes (MELAS). MELAS presents with normal early development, stroke-like episodes at a young age, encephalopathy, epilepsy, cognitive decline, lactic acidosis, and ragged-red fibers on skeletal muscle biopsy. Myoclonus and partial seizures are common but variable clinical features.1 Presently, the treatment of myoclonus and epilepsy in the setting of MELAS and MERRF and other nonsyndromic mitochondrial disorders is empiric and largely based on anecdotal experience. There are no published reports on the use of lamotrigine in these mitochondrial disorders. The mechanism of action of lamotrigine is incompletely understood but, in part, is thought to interact with voltage-gated sodium channels leading to modification of ion fluxes. In this report, we describe the enduring abolition of disabling myoclonus in a patient …