More than 75% of mutations in CHIP are accounted for by ASXL1, TET2 and DNMT3A, all evident in greater than 5% of MPN cases, whilst the next five most commonly affected genes JAK2, PPM1D, SRSF2, SF3B1 and TP53 are all identified at frequencies of around 2% in MPN with the exception of JAK2, an MPN driver very commonly identified as discussed [15, 117]. The gene discussed is SRSF2; the disease is myeloproliferative disorder.