Thyroid disorders typically fall into two categories: underactive (hypothyroidism) and overactive (hyperthyroidism). Hypothyroidism can be congenital, identified immediately after birth through the Colorado Newborn Screen. Symptoms are usually absent or very subtle in the newborn period, but lack of thyroid can lead to permanent mental retardation, and so prompt and thorough evaluation is critical. Hypothyroidism may also be acquired later in childhood or adolescence. This form can have a family pre-disposition as it often represents an autoimmune disorder. Symptoms can include fatigue, poor growth or pubertal development, weight gain, constipation, cold intolerance, sluggish intellectual performance, and irregular periods. Regardless of the underlying cause, the treatment of hypothyroidism is the same: thyroid hormone replacement therapy.

Hyperthyroidism is most commonly due to an autoimmune disorder called Graves disease. This is an autoimmune disorder that leads to overproduction of thyroid hormones. Symptoms can include over-activity, poor growth or pubertal development, lack of concentration, weight loss, diarrhea, heat intolerance, irregular periods, and rapid heart rate. Treatment includes an anti-thyroid medication and control of heart rate or blood pressure, if needed. A more permanent treatment involves destroying the thyroid gland with radioactive iodine, followed by thyroid hormone replacement.