A missense mutation in CLN8 causes progressive epilepsy with mental retardation (EPMR) or Northern epilepsy, which has so far been reported only from Finland and is now classified as an NCL.
Two types of NCL have so-far been found almost exclusively in Finland: Finnish variant late infantile NCL, vLINCL (CLN5), and the Northern epilepsy syndrome or Progressive epilepsy with mental retardation, EPMR (CLN8).