Individuals with Down syndrome have a higher incidence of endocrine problems than the general population. The endocrine system refers to a set of glands that include the thyroid, adrenal and pituitary glands.

What Is Hypothyroidism?

Hypothyroidism results from a malfunctioning thyroid gland. The thyroid gland is involved in various metabolic processes controlling how quickly the body uses energy, makes proteins and regulates hormones.  In hypothyroidism, the synthesis of the hormone thyroxin is decreased. Thyroxin is the hormone that promotes growth of the brain and other body tissue.

How Common Is Hypothyroidism?

Hypothyroidism is the most common endocrine problem in children with Down syndrome. It is estimated that approximately 10% of children with Down syndrome have congenital or acquired thyroid disease. Hypothyroidism is also common in adults with Down syndrome and can lead to symptoms of fatigue, mental sluggishness, weight fluctuations and irritability. Studies of adults with Down syndrome vary widely, but the incidence of thyroid disease in adults with Down syndrome is believed to be between 13% and 50%. Hypothyroidism can occur at any time from infancy through adulthood.

How Is Hypothyroidism Diagnosed?

Thyroid dysfunction is easily diagnosed through a screening 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 periodic intervals (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 are not hypothyroid, so the blood test for thyroid function is an important diagnostic test. Because the thyroid hormone affects normal development of the brain, testing of infants is particularly crucial.

What Treatment Exists for Hypothyroidism?

The thyroid hormone, thyroxin, is readily replaced through medication.

What Is Hyperthyroidism?

In this case, the thyroid gland is overactive. Symptoms are swelling in the neck, abnormal sweating and rapid pulse rate. No evidence exists as to whether hyperthyroidism is more prevalent in individuals with Down syndrome than in the general population.

What Is the Treatment for Hyperthyroidism?

This thyroid malfunction can be treated pharmacologically, blocking the synthesis of thyroid hormone through medication. It can also be treated with radioactive compounds to destroy the gland, or by surgically removing a portion of the thyroid gland.

Are People with Down Syndrome More Prone to Diabetes?

There is not sufficient data available at this point to know if there is 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.

Additional Resources:




  • Endocrinology chapter in Medical Care for Children and Adults with Developmental Disabilities. Second Edition. Botero, D., Fleischman, A. Baltimore, MD: Brookes Publishing. (2006)
  • The Thyroid and Down Syndrome. Leshin, Len. Down Syndrome and Health Issues.