MAP2K1 and congenital vascular malformation: Several somatic mutations in MAPK related genes, such as MAP kinase kinase 1 (MAP2K1 or MEK1), MAP kinase kinase kinase 3 (MAP3K3, or MEKK3), EPHB4 and TEK, have been found in congenital vascular malformations [63,64,66,82].