Matricardi S, Canafoglia L, Ardissone A, et al. - Researchers conducted this retrospective observational study to identify the prevalence of epilepsy in early-onset mitochondrial diseases (MDs) patients and to assess the epileptic phenotypes and associated characteristics. Participants in the study were 129 patients with a median age at disease onset of 3 months. They included children affected by MD with onset during the first year of life. Sixty-two out of 129 patients with early MD had epilepsy. It emerged in most patients as an early or presenting symptom within 12 months of life. The most detected epileptic syndromes were epileptic encephalopathy (EE) with spasms and EE with prominent focal seizures. In a multisystemic clinical presentation, epilepsy in children with early-onset MD can be a presenting or a prominent symptom. Factors related to epilepsy could determine the worst result of a seizure, leading to a more severe burden of the disease.