ASXL1 and chronic myelomonocytic leukemia: In CMML, ~40% of patients carry ASXL1 mutations, with the most frequent being the c.1934dupG; p.G646WfsX12 (~50%).7, 9 Although initially some investigators had considered c.1934dupG; p.G646WfsX12 to be a PCR artefact,57 subsequent studies have demonstrated its absence in germ-line DNA and control DNA, establishing it to be a bona fide mutation.20, 58 In CMML, ASXL1 mutations are associated with a proliferative phenotype, including higher WBC (white blood counts), higher absolute monocyte count (AMC) and the presence of circulating immature myeloid cells (IMC).7, 9, 20