Introduction
Individuals with Down syndrome experience higher rates of endocrine disorders compared to the general population. The endocrine system refers to the collection of glands responsible for producing hormones, the most notable of which include the thyroid gland, the adrenal glands, and the pituitary gland.
Part One: Hypothyroidism
What Is Hypothyroidism?
Hypothyroidism results from inadequate functioning of the thyroid gland, which contributes to numerous metabolic processes, regulates the body's rate of energy consumption, builds proteins, and governs hormone regulation. In hypothyroidism, the body produces insufficient amounts of thyroxine — the hormone responsible for promoting brain development and the growth of other tissues.
Prevalence
Hypothyroidism is the most common endocrine disorder in children with Down syndrome, with an estimated 10% affected by either congenital or acquired thyroid disease. It is also prevalent among adults with Down syndrome, where it can cause symptoms such as fatigue, mental sluggishness, weight fluctuations, and irritability. Although study findings vary considerably, it is estimated that between 13% and 50% of adults with Down syndrome are affected by thyroid disease, and the condition can develop at any point from infancy through to adulthood.
Diagnosis
Thyroid dysfunction is readily diagnosed through a blood test. All individuals with Down syndrome should be screened at birth and then periodically — at least every two years — thereafter. Testing should also be repeated promptly if new symptoms emerge, such as drowsiness, confusion, or mood changes.
Since some indicators of hypothyroidism — such as an enlarged tongue, constipation, and poor circulation — may also be present in individuals without the condition, blood testing for thyroid function constitutes an important diagnostic tool. Screening in infancy is of particular importance given the well-established effects of thyroid hormone on normal brain development.
Treatment
Thyroxine can be easily supplemented through medication.
Part Two: Hyperthyroidism
What Is Hyperthyroidism?
In this condition, the thyroid gland is overactive. Symptoms include swelling in the neck, abnormal sweating, and a rapid pulse rate. There is no evidence that hyperthyroidism occurs at a higher rate in individuals with Down syndrome than in the general population.
Treatment
Hyperthyroidism may be treated in one of three ways: medically, using drugs that inhibit thyroid hormone synthesis; with radioactive compounds that destroy the gland; or surgically, by removing part of the thyroid gland.
Part Three: Diabetes and Down Syndrome
Insufficient data are currently available to determine whether children with Down syndrome are at greater risk of Type 1 diabetes compared to others. However, research suggests that individuals who develop one type of autoimmune endocrine disorder — such as thyroiditis — are at increased risk of developing a second, such as Type 1 diabetes.
Source: Information in this section has been reproduced under an exclusive agreement with the National Down Syndrome Society (NDSS). Available at: www.ndss.org