PTPN11 and juvenile myelomonocytic leukemia: Catalytically activating heterozygous germline mutations in PTPN11 are associated with half of the cases of Noonan Syndrome (NS) and are also seen in blood cancers e.g. juvenile myelomonocytic leukemia (JMML), myelodysplastic syndromes and acute myeloid leukemia12–16.