Key entities included Wyburn-Mason syndrome, Cobb syndrome, Klippel-Trénaunay syndrome (KTS), neurofibromatosis type 1 (NF1), PHACE(S) syndrome, capillary malformation-AVM (CM-AVM), Parkes Weber syndrome (PWS), juvenile polyposis/HHT overlap (JP-HHT), HHT type 5 (BMP9/GDF2), PTEN hamartoma tumor syndrome (PHTS), and blue rubber bleb nevus syndrome (BRBNS). This evidence concerns the gene GDF2 and Down syndrome.