Gene mutations in JAK2, MPL, or CALR were not observed; however, mutations in genes including SRSF2 and SF3B1 occurred in this twin pair with childhood PMF.
Moreover, significantly more mutated splicing genes (SF3B1, SRSF2 and U2AF1) were present in PMF (0·60 mutated genes/patient) compared to ET (0·15) while no mutations in splicing genes were found in PV.
Myelofibrotic transformation was more frequent in patients with additional mutations, especially in SF3B1 (p = 0.02) and IDH1/2 (p < 0.0001) although a persistently high or a progressive increase of the JAK2V617F allele burden while receiving cytoreduction was the strongest predictor of MF transformation (HR 10.8, 95% CI 2.4-49.1, p = 0.002).