Epilepsy in mitochondrial disorders

OBJECTIVES Information about epilepsy in mitochondrial disorders is scarce although a number or syndromic and non-syndromic mitochondrial disorders frequently manifest with focal or generalized seizures. Aim of the review was to describe epilepsy in syndromic and non-syndromic mitochondrial disorders with epilepsy as a dominant or collateral feature of the phenotype. METHODS Literature search via Pubmed using the key words "mitochondrial", "epilepsy", "seizures", and all acronyms of syndromic mitochondrial disorders. RESULTS Syndromic mitochondrial disorders obligatory associated with epilepsy include Alpers-Huttenlocher-syndrome (AHS), ataxia neuropathy spectrum (ANS), Leigh-syndrome, MELAS-syndrome, myoclonic epilepsy, myopathy, and sensory ataxia (MEMSA) syndrome, and MERRF-syndrome, Occasionally, epilepsy is a phenotypic feature in IOSCA, KSS, LHON, LBSL, or NARP, All types of seizures occur but most frequently generalized tonic-clonic seizures, partial seizures, myoclonic jerks, or West-syndrome was reported. Treatment of epilepsy in patients with mitochondrial disorders is not at variance from epilepsy of other causes but mitochondrion-toxicity of various antiepileptic drugs, such as valproic acid, carbamazepine etc. has to be considered to avoid severe complications or deterioration of the underlying disease. CONCLUSIONS Epilepsy is a common phenotypic feature of syndromic as well as non-syndromic mitochondrial disorders. Treatment of epilepsy in mitochondrial disorders is not at variance from treatment of epilepsy due to other causes but mitochondrion-toxic drugs should be avoided.