CLN8 mutations result in two main phenotypes: one is Northern epilepsy (NE), a progressive epilepsy with mental retardation (EPMR) prevalent in Finland; the other one is late‐infantile NCL, primarily reported in Turkey, characterized by severe cognitive impairment and loss of mobility within 2–4 years [91, 92, 93]. This evidence concerns the gene CLN8 and epilepsy.