PTPN11 and Costello syndrome: RASopathies group include: Noonan syndrome (NS) caused by mutations in PTPN11, SOS1, RAF1, KRAS, NRAS and CBL; NS-like with loose anagen hair (NSLAH) due to germline mutations of SHOC2 [6] or more rarely, PPP1CB [7]; NS with multiple lentigines (NSML) caused by specific mutations of PTPN11 [8], although other rare mutations have been reported [9]; Costello syndrome (CS) caused by activating mutations in HRAS; cardio-facio-cutaneous syndrome (CFC) caused by gain of function mutations in BRAF and MAP2K1 or MAP2K2 [1].