RAF1 and RASopathy: The most common RASopathy, Noonan Syndrome (NS), can be caused by germ-line gain-of-function PTPN11, KRAS, NRAS, RRAS, SHOC2, SOS1/2, RAF1, RIT1 or PPP1CB alleles12, 15, 16, 17, 18, 19, 20.