PTPN11 and Noonan syndrome: This group of diseases, also known as RASopathies, includes neurofibromatosis 1 (NF1 mutations), Costello syndrome (HRAS mutations), Noonan syndrome, and such Noonan-like syndromes as Noonan syndrome-like disorder with loose anagen hair and the LEOPARD syndrome (mutations in PTPN11, SOS1, KRAS, NRAS, RAF1, BRAF, MEK1, SHOC2, MEK2, RIT1, and CBL) [41, 45–47].