• Congenital defects of the gland or how it works • Iatrogenic—occurs as the result of surgery or radiation therapy for thyroid cancer treatment • Iodine deficiency—rare in the US • Pituitary deficiency • Unknown reasons
• Congenital defects of the gland or how it works• Iatrogenic—occurs as the result of surgery or radiation therapy for thyroid cancer treatment• Iodine deficiency—rare in the US• Pituitary deficiency• Unknown reasons