The underlying mechanism of derangement in the thyroid hormone levels and/or metabolism in CKD is caused by both general and kidney-specific factors such as reduced bioactivities of thyrotropin-releasing hormone (TRH) and TSH, loss of thyroid hormone binding proteins during dialysis, modified entry of the thyroid hormone into tissue, altered expression of iodothyronine deiodinases, changes in thyroid hormone receptor expression or function, iodide retention, anemia, and comorbidities associated with CKD [11,12]. The gene discussed is TRH; the disease is anemia (phenotype).