TPO and cyclic hematopoiesis: In humans with CH, variants of some genes associated with the development of dysgenesis and dyshormonogenesis have been reported, the latter being inherited in a recessive manner [2], and related to mutations in genes such as TPO (thyroperoxidase), DUOX2, DUOXA2, SLC26A4, SLC5A5, TG and IYD [1,2,4].