Germline monoallelic pathogenic variants in PTPN11, KRAS, HRAS, BRAF, RAF1, RIT1, SOS1, SOS2, and RASA1 have been identified in individuals with CCLA and Noonan syndrome, CCLA and Costello syndrome, CCLA and cardiofaciocutaneous syndrome, or CCLA and capillary malformation-arteriovenous malformation syndrome (48, 61, 80–88). Here, PTPN11 is linked to Noonan syndrome.