TTF2 and cyclic hematopoiesis: We also designed a target sequencing panel including 13 causative genes: DUOX2, TG, TPO, TSHR, TTF1, TTF2, PAX8, NKX2-5, GNAS, THRA, TSHB, IYD and SLC5A5, to identify the spectrum and prevalence of disease-causing gene mutations in Chinese CH patients.