Mitochondrial disorders and epilepsy

Mitochondrial respiratory chain defects (RCD) often exhibit multiorgan involvement, affecting mainly tissues with high-energy requirements such as the brain. Epilepsy is frequent during the evolution of mitochondrial disorders (30%) with different presentation in childhood and adulthood in term of type of epilepsy, of efficacy of treatment and also in term of prognosis.

Mitochondrial disorders can begin at any age but the diseases with early onset during childhood have generally severe or fatal outcome in few years. Four age-related epileptic phenotypes could be identified in infancy: infantile spasms, refractory or recurrent status epilepticus, epilepsia partialis continua and myoclonic epilepsy. Except for infantile spasms, epilepsy is difficult to control in most cases (95%). In pediatric patients, mitochondrial epilepsy is more frequent due to mutations in nDNA-located than mtDNA-located genes and vice versa in adults. Ketogenic diet could be an interesting alternative treatment in case of recurrent status epilepticus or pharmacoresistant epilepsy.

Epileptic seizures increase the energy requirements of the metabolically already compromised neurons establishing a vicious cycle resulting in worsening energy failure and neuronal death.