For some genes, such as GRIN2A, which codes for severe forms of idiopathic focal epilepsy, and PCDH19, which has similarities to Dravet syndrome, the therapeutic concepts of these forms of epilepsy may also apply to these genes (33, 37). The gene discussed is PCDH19; the disease is encephalopathy, progressive, early-onset, with brain edema and/or leukoencephalopathy.