MEN syndrome is a rare and inherited disorder that causes the endocrine glands to develop tumors.

The most common thyroid diseases are hyperthyroidism, hypothyroidism or goiters. They are the result of your thyroid gland overproducing or underproducing the thyroid hormone. The thyroid gland produces hormones that regulate your metabolism and affect nearly every vital function in your body, including your heart rate, body temperature, breathing, and muscle mass.