POLG and MELAS: In certain mitochondrial diseases, seizures are part of a syndrome—e.g., in Alpers–Huttenlocher syndrome (AHS) and other phenotypes associated with a pathogenic variant in the POLG gene, in a deficit of pyruvate dehydrogenase complex (PDHc), myoclonic epilepsy with ragged red fibres (MERRF), MELAS, or in Leigh syndrome.