TPO and cyclic hematopoiesis: Of the 21 candidate genes for CH analyzed in this study, the gene with the highest frequency of biallelic mutations was DUOX2, followed by TPO, TG and TSHR. We identified 120 non-silent variants of DUOX2 distributed in 51 mutation sites in 66 patients, of which, 41 (41/110, 37.27%) carried biallelic mutations (Fig. 2).