Individuals with Down syndrome are more likely to have endocrine problems than the general population. The endocrine system is a set of glands in the body including the thyroid, adrenal, and pituitary glands.
Hypothyroidism results from a faulty thyroid gland. The thyroid gland is involved in controlling how quickly the body uses energy, makes proteins, and regulates hormones. In hypothyroidism, the creation of the hormone thyroxin is decreased. Thyroxin is the hormone that promotes growth of the brain and other body tissue.
Hypothyroidism is the most common endocrine problem in children with Down syndrome. It is estimated that 2-7% of children with Down syndrome have congenital (have it at birth) or acquired (developed later in life) thyroid disease (Bull et al., 2022). Hypothyroidism is also common in adults with Down syndrome and can lead to tiredness, slow thinking, changing weight, and irritability. The incidence of thyroid disease in adults with Down syndrome is believed to be between 39% and 61% (Tsou et al., 2020). Hypothyroidism can occur at any time from infancy through adulthood.
Thyroid dysfunction is easily diagnosed by a blood test that can be performed by a primary care doctor. All individuals with Down syndrome should be tested for hypothyroidism at birth and at least every two years thereafter. Doctors should also consider testing patients with Down syndrome if any new symptoms of sleepiness, confusion or mood changes occur. Some indicators of hypothyroidism — enlarged tongue, constipation, poor circulation — are also found in individuals who do not have hypothyroidism, so the blood test for thyroid function is an important test for diagnosis. Because the thyroid hormone affects normal development of the brain, testing of infants is particularly important.
Treatment for Hypothyroidism
The thyroid hormone, thyroxin, is readily replaced through medication.
In this case, the thyroid gland is overactive. Symptoms are swelling in the neck, abnormal sweating, and rapid heart rate. No evidence exists as to whether hyperthyroidism is more prevalent in individuals with Down syndrome than in the general population.
Treatment for Hyperthyroidism
This thyroid malfunction can be treated with medication. It can also be treated with radioactive compounds to destroy the thyroid gland or by surgically removing a portion of the gland.
There is not sufficient data available at this point to know if there is an increased risk for children with Down syndrome to develop type one diabetes as compared to the rate for their peers in the general population. However, research suggests that individuals who develop one type of endocrine autoimmune disorder, such as thyroiditis, are more likely to develop a second disorder, such as type one diabetes.
Bull M, Trotter T, Santoro S, Christensen C, Grout RW, THE COUNCIL ON GENETICS; Health Supervision for Children and Adolescents With Down Syndrome. Pediatrics May 2022; 149 (5): e2022057010. 10.1542/peds.2022-057010
Tsou AY, Bulova P, Capone G, et al. Medical Care of Adults With Down Syndrome: A Clinical Guideline. JAMA. 2020;324(15):1543–1556. doi:10.1001/jama.2020.17024
American Thyroid Association
Promotes thyroid health and understanding thyroid biology
American Diabetes Association
Aims to improve the lives of all people affected by diabetes
Advocate Health: Diabetes in Adults with Down Syndrome
Global Down Syndrome Foundation: https://www.globaldownsyndrome.org/wp-content/uploads/2021/06/2021-GLOBAL-Guideline-Diabetes-Toolkit.pdf