PCDH19 and epilepsy: The pathophysiology of PCDH19-related epilepsy has also been reviewed recently with four main theories: gamma-aminobutyric acid type A receptor [GABAA(R)] dysregulation, cellular interference, blood-brain barrier dysfunction, and the aldo-keto reductase 1C family 1-3 (AKR1C1-3) gene product shortage (26).