Approach to the patient: genetics and management of congenital hypothyroidism.

Congenital hypothyroidism (CH) encompasses a diverse spectrum of disorders with diverse genetic etiologies and variable clinical courses, ranging from transient neonatal hyperthyrotropinemia to permanent thyroid hormone or thyrotropin deficiency. Advances in molecular genetics have substantially expanded the catalog of genes implicated in CH; however, the translation of this knowledge into everyday clinical practice remains challenging. In this Approach to the Patient, we use selected clinical vignettes to illustrate how genetic information can substantiate the diagnosis, management, and counseling of patients with CH. Rather than providing an exhaustive genetic review, this paper focuses on clinically relevant scenarios and pragmatic decision points-when to perform genetic testing, how results influence treatment duration and intensity, and how they guide prognostication and family counseling. This case-based framework emphasizes a pragmatic, patient-centered approach to the use of genetics in the management of CH.