Conditional deletion of BCL-XL in the megakaryocytic lineage causes a profound shortening in platelet lifespan, consequent thrombocytopaenia and reactive megakaryocytosis.5 Consistent with this, vehicle-treated BclxPf4Δ/Pf4Δ mice exhibited thrombocytopaenia and increased megakaryocyte counts (Figures 4a and b). This evidence concerns the gene BCL2L1 and Thrombocytopenia.