According to previous reports, the cause of CH in approximately 80%–85% of patients is thyroid dysgenesis (including agenesis, ectopy, and hypoplasia), which is related to gene mutations in TSHR, PAX8, TTF1/NKX2-1, and TTF2/FOXE1. The gene discussed is NKX2-1; the disease is cyclic hematopoiesis.