ILAE genetic literacy series: Focal cortical dysplasia

Focal cortical dysplasia (FCD) is a common cause of drug-resistant focal epilepsy in children and young adults and is often surgically remediable. The genetics of FCD are increasingly understood due to the ability to perform genomic testing including deep sequencing of resected FCD tissue specimens. There is clear evidence that FCD type II occurs secondary to both germline and somatic mTOR pathway variants, while emerging literature supports the role of SLC35A2, a glycosylation gene, in mild malformation of cortical development with oligodendroglial hyperplasia and epilepsy (MOGHE). Herein, we provide a review of FCDs focusing on their clinical phenotypes, genetic basis, and management considerations when performing genetic testing in this patient group.