Analysis of longitudinal data estimated a 10-fold elevated risk of developing a haematological malignancy for individuals with any acquired chromosome anomaly,4 and a similar risk was estimated for individuals with somatic mutations in genes known to be associated with myeloid malignancies.30, 31 The most commonly mutated genes in population cohorts were DNMT3A, TET2 and ASXL1, and the finding that most individuals had only a single abnormality suggested that mutations in these genes are often initiating events for clonal haemopoiesis. Here, TET2 is linked to myeloid neoplasm.