PTPN11 and juvenile myelomonocytic leukemia: In this regard, analysis of the mutational spectra observed in NS vs JMML patients clearly indicates that germline PTPN11 NS-associated mutations have only a mild effect on development and hematopoiesis when compared with JMML-associated somatic PTPN11 lesions.15, 16, 17, 18, 19