Trhr, the thyrotropin-releasing hormone receptor gene, encodes a G-protein coupled receptor with seven transmembrane domains [5]. It is crucial in the hypothalamo-pituitary-thyroid axis, where it binds thyrotropin-releasing hormone (TRH), triggering a signaling cascade that regulates the production and release of thyroid-stimulating hormone (TSH), thus influencing thyroid hormone synthesis. This process is vital for normal growth, metabolism, and development [2,3,4,5].

Mutations in Trhr can lead to various disorders. A homozygous missense mutation in TRHR (c.392T > C; p.I131T) was identified in a consanguineous family, causing central hypothyroidism in homozygotes and hyperthyrotropinemia in heterozygotes. The mutation decreases TRH affinity, disrupts the interaction between the receptor and Gq, and impairs signaling [2]. In thyroidectomized patients, genetic variants of the TRHR gene are associated with hypothalamo-pituitary sensitivity to levothyroxine, as different genotypes result in varying TSH levels and thyroid hormone ratios [3]. Also, the rs7832552 T allele of TRHR has been associated with power-related athletic performance [1].

In conclusion, Trhr is essential for the normal functioning of the hypothalamo-pituitary-thyroid axis. Studies on Trhr mutations and variants have revealed its role in central hypothyroidism and in the regulation of hypothalamo-pituitary sensitivity to thyroid hormone replacement therapy. Additionally, its association with athletic performance broadens our understanding of its potential influence on physiological capabilities.