Previous research based on large samples found that CH is largely the result of mutations in fixed “early” mutational events: The genes that encode epigenetic modifiers, DNMT3A and TET2, are the two most common mutations; the third most commonly mutated gene was ASXL1, whereas mutations in splicing factors (SF3B1, SRSF2, PRPF8, and U2AF1) were also frequent (72). This evidence concerns the gene U2AF1 and cyclic hematopoiesis.