Our previous analysis of MPN patients bearing concomitantly JAK2-R1063H and V617F mutations revealed increased incidence of thrombotic events [14], so we asked whether the increased mortality in the cohort of Jak2-R1063H mice (which occurred suddenly precluding pathological analysis) (Fig. 1A) could be related to platelet pathology, similar to that observed for JAK2-V617F [17, 48]. This evidence concerns the gene JAK2 and myeloproliferative neoplasm.