PTPN11 and juvenile myelomonocytic leukemia: NS has also been associated with the simultaneous occurrence of ALL and JMML in the same patient, as reported by Pauli et al. They presented a girl with NS harboring a PTPN11 germline mutation c.417 G>C (p.E139D) who developed BCP-ALL at 16 months of age; during remission, at 4 years of age, JMML was diagnosed.