A rare cause of progressive myoclonic epilepsy: KCTD7 mutation

'Progressive myoclonic epilepsy 3' (PME3), which occurs in KCTD7 gene mutations, is an autosomal recessive disease with severe neurodegeneration. Although it is known that progressive myoclonic epilepsies may occur due to lysosomal storage diseases, metabolic diseases and many other degenerative diseases, it has been revealed recently that progressive myoclonic epilepsies associated with channelopathies also exist. In this article, two epileptic encephalopathy cases with KCTD7 homozygous mutation in whole exome analysis are presented. The parents of both cases were consanguineous and were carriers for the mutation. Their development was normal until 2.5 years of age in the first case and until 1 years of age in the second case. The patients had significant progressive psychomotor regression after the onset of myoclonic and atonic seizures in the form of head drop. No abnormality was detected in metabolic tests and cranial magnetic resonance imaging in both patients. Multifocal epileptic discharges and occasional 'ESES' (electrical status epilepticus in sleep) pattern were observed in electroencephalograms. Seizure-freedom could not be achieved in both patients despite anti-seizure polytherapy. In this article, it is aimed to emphasize that KCTD7 mutation is one of the causes of channelopathy-related progressive myoclonic epilepsies.
Keywords: Epileptic encephalopathy, KCTD7 gene, progressive myoclonic epilepsy