Thyroglobulin (TG) is a protein synthesized by follicular cells of the thyroid, and is the precursor for thyroid hormones T3 and T4. Serum thyroglobulin measurements can be used as a marker for thyroid tumors, particularly in the postoperative management period, as well as a sensitive biomarker of iodine status in iodine deficiency states. Mutations in this gene are implicated in thyroid dyshormonogenesis with goiter, and congenital hypothyroidism. Polymorphisms are associated with autoimmune thyroid diseases such as Grave’s and Hashimoto’s thyroiditis. References: Nature Clin Practice 2008 4(4):223; Thyroid 2014 24(8):1195; Clin Endocrin 2004 61(2):263; Mol Med Reports 2015 12(3):4469