Here, we studied the effects of Dnmt3a haploinsufficiency combined with Ptpn11D61Y, a gain-of-function mutation in the protein tyrosine phosphatase SHP2, which is the most commonly mutated gene in juvenile myelomonocytic leukemia (JMML) and is used as a mouse model of myeloproliferative disease [9]. The gene discussed is PTPN11; the disease is juvenile myelomonocytic leukemia.