In contrast, in one patient (PD11408, Fig.3), a JAK2 mutation occurred as a secondary event within an SF3B1 clone (this individual had refractory anaemia with ringed sideroblasts and thrombocytosis) and this individual did not have any additional post-JAK2 clonal evolution in the 5 years preceding an MF diagnosis. The gene discussed is JAK2; the disease is thrombocytosis disease.