Hypothyroidism is a condition in which the thyroid gland, located in the front of the neck, does not produce enough thyroid hormones, which control overall body metabolism. Hypothyroidism can have several causes, including an autoimmune disorder in which the body’s immune system mistakenly destructs its own thyroid gland. Undiagnosed hypothyroid children may experience slowed growth rate. Additional symptoms include sluggishness, pallor, increased sensitivity to cold and constipation. Replacement therapy with synthetic thyroid hormones in the form of a single daily tablet is usually given. Thyroid hormones are critical for normal brain development in babies and children, therefore treatment with the correct dose of synthetic hormone is very important. Because the body can require higher doses of synthetic hormone over time, the child should be retested periodically to make sure the right amount of hormone is given and the dose is adjusted as needed.