Longer telomeres predispose to DNMT3A-mutant CH, perhaps by extending cellular replicative potential, whereas this is not the case for some other CH driver genes, including PPM1D. It is notable that PPM1D-mutant CH is known to be particularly enriched among individuals with inherited short telomere disorders54 and in individuals exposed to DNA-damaging chemotherapies that appear to shorten telomeres56–58. Here, DNMT3A is linked to cyclic hematopoiesis.