Recently, gain-of-function Pik3ca mutations have been shown to be sufficient to drive small, postnatal capillary hemangiomas in brain endothelial cells and are necessary, in combination with mutations of known CCM genes in mice or in humans, for the development of large postnatal cavernomas (Hong et al., 2021; Ren et al., 2021). This evidence concerns the gene PIK3CA and cavernous hemangioma.