Linkage analysis using DNA markers linked to the EPM1 gene for progressive myoclonus epilepsy of Unverricht-Lundborg type showed that the Northern epilepsy syndrome is not allelic to EPM1.
EPMR patients were homozygous for a missense mutation (70C-->G, R24G) that was not found in homozygosity in 433 controls.We also cloned the mouse Cln8 sequence.
EPMR patients were homozygous for a missense mutation (70C-->G, R24G) that was not found in homozygosity in 433 controls.We also cloned the mouse Cln8 sequence.
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).
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).
Mutations in the CLN8 gene underlie Northern epilepsy (progressive epilepsy with mental retardation [EPMR], OMIM 600143) and a subset of Turkish variant late infantile NCL, but the pathogenetic mechanisms have remained elusive.
In the remaining families, four CLN8 gene mutations were identified indicating that in a subset of patients with Turkish vLINCL, the disorder is allelic to Northern epilepsy.
We recently performed whole-exome sequencing in two families with affected siblings and then carried out a follow-up study and identified ceroid-lipofuscinosis neuronal 8 (epilepsy, progressive with mental retardation) (CLN8) as a potential genetic risk factor for ASD.
CLN8 mutation was first identified in Finnish patients, and the condition was named Northern Epilepsy (NE); however, the severe phenotype of the CLN8 gene was subsequently found outside Finland and named 'variant late-infantile' NCL.