Compared to individuals without CH, several studies have identified suboptimal psychomotor development in infancy, adolescence and extending into adulthood in the presence of CH.4, 5, 6, 7, 8, 9, 10, 11 In addition to the timing and severity of thyroid hormone deficiency, developmental outcomes can also be influenced by the time of diagnosis, age of treatment onset, dose of thyroid hormone replacement, age of thyroid hormone normalization and family adherence to treatment. The gene discussed is TG; the disease is cyclic hematopoiesis.