Our study focused on the spectrum of thyroid function in CS patients, revealing a notable incidence of thyroid hormone alterations, including decreased levels of triiodothyronine (TT3), thyroxine (TT4), free T3 (FT3), free T4 (FT4), and thyroid-stimulating hormone (TSH) below the reference values in a substantial proportion of our cohort. Here, TG is linked to Cowden syndrome 1.