Focal cortical dysplasia as a cause of epilepsy: The current evidence of associated genes and future therapeutic treatments

Focal cortical dysplasias (FCDs) are the most common cause of treatment-resistant epilepsy affecting the pediatric population. Most individuals with FCD have seizure onset within the first five years of life and the majority will develop epilepsy by the age of sixteen. Many cases of FCD are postulated to be the result of abnormal brain development in utero by germline or somatic gene mutations regulating neuronal growth and migration during corticogenesis. Other cases of FCD are thought to be related to infections during brain development, with other causes still not fully determined. Typical anti-seizure medications are oftentimes ineffective in FCD. In addition, surgical intervention is often unable to be successfully performed due to the involvement of eloquent areas of the brain or insufficient resection of the epileptogenic focus, posing a challenge for physicians. The genetic nature of FCDs provides an avenue for drug development with several genetic and molecular targets undergoing study over the last two decades, with the most widely studied target being mammalian target of rapamycin (mTOR). However, other molecular targets of FCD have been identified and provide a rich field of opportunity to expand current understanding and subsequentlydesign targeted molecular therapy to improve the lives of patients with FCDs. To better inform this area of ongoing research, we performed a narrative review of the molecular markers and potential therapeutic drugs for FCDs.