In the group with hypothyroidism, CH was more likely to occur in patients who had a lower BMI, lower thyrotropin level, abnormal pituitary imaging, and panhypopituitarism (Table 2 and Table 3).12,23,24,25,26 We also identified a case of isolated CH confirmed with a TRH stimulation test in the absence of other hypothalamic-pituitary hormonal axis dysfunction. The gene discussed is TRH; the disease is cyclic hematopoiesis.