These mutations are already well described in the following disorders: Neurofibromatosis type I—NF1 gene; Noonan syndrome (NS)— PTPN11, SOS1, RAF1, KRAS, NRAS, SHOC2, and CBL genes; Noonan with multiple lentigines or LEOPARD syndrome—PTPN11 and RAF1 genes; Legius syndrome—SPRED1 gene; Costello syndrome (CS)—HRAS gene; Cardiofaciocutaneous syndrome (CFC)—BRAF and MAP2K1 or MAP2K2 genes; and Capillary malformation-arteriovenous malformation syndrome (CM-AVM)—RASA1 gene (Tidyman and Rauen, 2016). The gene discussed is PTPN11; the disease is Legius syndrome.