Of interest, most of the DDX41-MPNs (10 out 13), also harbor co-occurring MPN disease-causing mutations (JAK2 = 6, CALR = 3, MPL =1), which correlates with findings of JAK2-mutated MPNs in other DDX41-MPNs previously reported (3). The gene discussed is JAK2; the disease is myeloproliferative disorder.