KRIT1 and cerebral cavernous malformation: To test this directly, we utilized Krit1ieKO mice, which develop lesions similar to those seen in human CCM patients.15 Tamoxifen injection of PDGFB‐iCreERT2Krit1flox/flox mice at P1 stimulates endothelial‐specific Cre‐mediated recombination and loss of Krit1 protein in >90% of the endothelium.