IYD and hyperinsulinemic hypoglycemia, familial, 4: The genes associated with this disease cause alterations in the synthesis of thyroid hormones, including defects in the transport of iodine to the thyrocyte (SLC5A5/NIS), defects in the organification of iodine (TPO, DUOX1, DUOX2, DUOXA2, SLC26A4, and SLC26A7), alterations in the synthesis of thyroglobulin (TG), or iodotyrosine deiodinase deficiency (IYD/DEHAL1) [8].