PTPN11 and Noonan syndrome: There is also an association between Noonan syndrome (a neuro-cardio-facial-cutaneous syndrome) characterized by germ-line mutations of MAP kinase pathway genes (PTPN11, SOS1, KRAS, NRAS, RAF1, BRAF, SHOC2 and CBL) [3, 50] and PA (as well as other malignancies).