PA8 gene heterozygous mutations are associated with Permanent CH(PCH), TSHR heterozygous mutations are associated with TSH elevation, TSHR with DUOX2/TG heterozygous mutations are associated with CH, most single or multiple DUOX2 mutations are associated with Transient CH (TCH) or TSH elevation and multiple DUOX2 mutation sites are associated with PCH. Here, DUOX2 is linked to cyclic hematopoiesis.