Genetics of epilepsy

More than 3% of people will develop epilepsy during their lifetime (at least 2 unprovoked seizures within 2 years) with approximately 40% manifesting during childhood and 50% of genetic origin. More than 280 single gene diseases may be associated with epilepsy. Besides metabolic disorders and malformations involving the CNS, many types of epileptic encephalopathy belong to this group. However, 98-99% of common idiopathic epilepsies follow a complex (polygenic) mode of inheritance. Ion channels defects have been identified as the cause only in selected families and isolated cases. Recently, it could be shown that about 3% of individuals with idiopathic epilepsy carry genomic copy number variants (CNV), mostly deletions, containing 1-10 genes. Some of these DNA segments contain ion channel genes or genes required for CNS development. However, these findings are not useful for genetic counseling. Current methods of molecular biology (e.g exome sequencing) have already started to open a new area in the field of epilepsy genetics.