Epilepsy in Mitochondrial Disorders

Mitochondrial encephalopathies (MEs) are characterized by an extreme clinical heterogeneity since they can involve different systems and manifest at distinct ages with variable course. Many affected individuals display a cluster of clinical features that fall into discrete syndromes among syndromic pictures, epilepsy is relevant in myoclonic epilepsy with ragged-red fibers (MERRF), mitochondrial encephalomyopathy with lactic acidosis and stroke-like episodes (MELAS), neurogenic weakness with ataxia and retinitis pigmentosa (NARP), Alpers’ encephalopathy and Leigh syndrome (LS). However, many patients do not fit neatly into one particular syndrome, due to “overlapping” presentations (sharing symptoms of different syndromes) or atypical clusters of symptoms. Epilepsy is a frequent symptom also in non-syndromic patients, sometimes dominating the clinical presentation.