CCM2 and cerebral cavernous malformation: Blood vessel development in the mouse brain starts at E7 with the development of the earliest blood islands and terminates postnatally around P19.6 Thus, angiogenesis is still occurring in the brain vasculature during the first week of postnatal life, correlating with the reported developmental window for Ccm2 deletion required to form CCM lesions.7 Angiogenesis is driven by the expression and activity of vascular endothelial growth factor (VEGF), a pro‐mitotic and pro‐migratory growth factor intimately linked with endothelial activation and angiogenesis.