PTPN11 and RASopathy: SHP2 is a SH2 domain-containing protein tyrosine phosphatase encoded by the gene PTPN11, which has been known for over two decades to promote RAS-driven mitogen-activated protein kinase (MAPK) signaling, and activating PTPN11 mutations are one of the common causes of RASopathies, developmental syndromes defined by hyperactive RAS-MAPK signaling16.