Missense mutations in vascular endothelial growth factor receptor 2 (VEGFR2) and variants of ring finger protein 213 (RNF213), associated with PHACE syndrome, are additional factors, along with placental abnormalities (such as placenta previa and preeclampsia), disruptions in placental circulation, advanced maternal age, and prematurity. This evidence concerns the gene KDR and placenta praevia.