Natural history of clonal haematopoiesis seen in real‐world haematology settings

Summary Recursive partitioning of healthy consortia led to the development of the Clonal Hematopoiesis Risk Score (CHRS) for clonal haematopoiesis (CH); however, in the practical setting, most cases of CH are diagnosed after patients present with cytopenias or related symptoms. To address this real‐world population, we characterize the clinical trajectories of 94 patients with CH and distinguish CH harbouring canonical DNMT3A/TET2/ASXL1 mutations alone (‘sole DTA’) versus all other groups (‘non‐sole DTA’). TET2 , rather than DNMT3A , was the most prevalent mutation in the real‐world setting. Sole DTA patients did not progress to myeloid neoplasm (MN) in the absence of acquisition of other mutations. Contrastingly, 14 (20.1%) of 67 non‐sole DTA patients progressed to MN. CHRS assessment showed a higher frequency of high‐risk CH in non‐sole DTA (vs. sole DTA) patients and in progressors (vs. non‐progressors). RUNX1 mutation conferred the strongest risk for progression to MN (odds ratio [OR] 10.27, 95% CI 2.00–52.69, p = 0.0053). The mean variant allele frequency across all genes was higher in progressors than in non‐progressors (36.9% ± 4.62% vs. 24.1% ± 1.67%, p = 0.0064). This analysis in the post‐CHRS era underscores the natural history of CH, providing insight into patterns of progression to MN.