Defects of the human Filamin-A gene also cause X-linked periventricular nodular heterotopia (PNH), a malformation of neuronal migration characterized by nodules of neurons in inappropriate location adjacent to the walls of the lateral ventricles, having failed to migrate away from the embryonic ventricular zone to the developing cerebral cortex [7, 8]. The gene discussed is FLNA; the disease is paroxysmal nocturnal hemoglobinuria.