Complex/polygenic inheritance.
As the genetic etiology is complex/polygenic, pathogenic single gene disorders are not expected and genetic testing is not part of routine clinical evaluation. If seizures are drug-resistant or the individual has intellectual impairment, a chromosomal microarray is recommended to look for recurrent copy number variations (e.g., 15q11.2, 15q13.3, and 16p13.11 microdeletions). If absence seizures begin <4 years of age, 10% have glucose transporter 1 deficiency syndrome (due to pathogenic variants in SLC2A1).
A first-degree family history of epilepsy may be present, in keeping with complex inheritance. Family members typically have a genetic generalised, usually an idiopathic generalized epilepsy syndrome.