PCDH19 and Epileptic encephalopathy: Researchers generated human cortical organoids using homologous female hESCs with mixed wild type (WT) or homozygous PCDH19 knockout (KO), uncovering the critical role of PCDH19 in human ventricular zone radial glial tissue and early cortical development.[187] Additionally, a study utilized hESCs edited for the tumor suppressor gene WW domain‐containing oxidoreductase (WWOX) and patient‐derived iPSCs to establish brain organoids modeling developmental and epileptic encephalopathy (DEE) in vitro.