The Link Between Down Syndrome and Hypothyroidism

Thyroid disease is one of the common manifestations of Down syndrome. Hypothyroidism (an underactive thyroid) is the type that most frequently occurs, and it is estimated that 13 percent to 55 percent of people with Down syndrome will develop the condition over the course of their lifetime (on average, thyroid disease affects approximately 12 percent of the general population). Those with Down syndrome are also at increased risk for other thyroid concerns, such as hyperthyroidism (an overactive thyroid).

Down's syndrome, also known as trisomy 21 occurs when a child is born with an extra copy of chromosome 21. The extra chromosome causes all of the effects of Down syndrome, including thyroid disease.

Thyroid Conditions in Down Syndrome

Thyroid disease has been recognized as the most common endocrine problem associated with Down syndrome.

Some of the thyroid conditions associated with Down syndrome include:

• Hashimoto's thyroiditis (HT): HT is an autoimmune disease in which the body makes antibodies (immune proteins) that attack the thyroid gland. HT usually causes hypothyroidism. If you have Down syndrome and HT, it may begin at any age between infancy and in early adulthood. With Down syndrome, HT can manifest with hypothyroidism or hyperthyroidism in the early years after diagnosis, and then may progress to Grave's disease in later years.
• Grave's disease: Grave's disease is an autoimmune disorder of the thyroid gland, which usually manifests with hyperthyroidism. It can also cause protrusion of the eyes or vision changes. Grave's disease may produce serious symptoms, especially if left untreated, including a severe episode of hyperthyroidism called thyroid storm.
• Thyroid dysgenesis: Sometimes the thyroid gland does not form properly in infants with Down syndrome, a condition described as thyroid dysgenesis. This usually causes congenital hypothyroidism, which is diagnosed at birth.

Recognizing Thyroid Disease in Down Syndrome

With Down syndrome, thyroid disease can be present at birth or it can develop later. Some signs to look for include:

• Fatigue: Tiredness, lack of energy, and a need for excessive sleep are all characteristic of hypothyroidism. As your young baby is growing, it can be tough to gauge how much sleep is normal. If your child begins to have altered sleep habits or seems to have less energy or more energy (a sign of hyperthyroidism), be sure to discuss these changes with your child's healthcare provider.
• Temperature intolerance: Hyperthyroidism can make a person intolerant of warm temperatures, and hypothyroidism can make a person feel cold all the time. Unusual responses to temperature often warrant thyroid testing.
• Weight changes: Down syndrome is characterized by a short, stocky appearance and a full appearing face. This can make it difficult to recognize unusual weight gain, which occurs with hypothyroidism. If you or your child have Down syndrome, be aware that weight changes, including weight loss (a sign of hyperthyroidism), can signal thyroid disease.
• Trouble concentrating: All types of thyroid disease can interfere with concentration. Because Down syndrome is associated with learning difficulties, it can be difficult to recognize this concern. As with many of the other symptoms of thyroid disease, new symptoms can be a tip-off that you need to look deeper into the cause.

However, thyroid disease symptoms in children—even those who don't have Down syndrome—can be a bit difficult to recognize for a variety of reasons:

• Kids are still developing physically and mentally.
• A child's mood, energy level, appetite, and need for sleep can all vary during growth spurts and at different stages during adolescence.
• Some characteristics of Down syndrome can distract from thyroid symptoms.
• Children may not be able to effectively communicate how they are feeling.

Bring up any concerns you have, even if you feel they could be tied to Down syndrome rather than another diagnosis, with a healthcare provider.

Subclinical Thyroid Disease

If you or your child has Down syndrome, you may notice the symptoms of thyroid disease, or you can have subclinical thyroid disease, which is characterized by abnormalities in thyroid hormone levels without obvious symptoms.

Subclinical thyroid disease can cause long-term complications if it is left untreated. This means that it is important to be aware of the risk and to regularly follow screening recommendations, which can identify the problem at an early stage before complications develop.

Screening

Most infants in the United States, with and without Down syndrome, are screened for congenital hypothyroidism at birth through a newborn screening program. If the newborn thyroid screening test is positive (abnormal), or if you or your healthcare provider sees any signs of thyroid disease in your newborn, your baby may need further diagnostic tests.

In addition to blood tests, your child may also need to have imaging studies of the thyroid gland, such as ultrasound, computerized tomography (CT) scan, or magnetic resonance imaging (MRI) to determine if there is a problem with the growth and development of the thyroid gland.

Treatment

Medical treatment for thyroid disease includes thyroid replacement medications, or antithyroid medications, depending on whether the problem is hypothyroidism or hyperthyroidism.

Treatment is generally effective, but, as your child grows, medication doses need to be adjusted periodically to accommodate changes in metabolism, weight, and thyroid function.

A Word From Verywell

If you have Down syndrome, addressing health issues such as thyroid disease can help you feel healthy and enjoy life, maximizing your potential. If you are a parent of a child with Down syndrome, recognizing and treating medical problems like thyroid disease can give your child a huge advantage as he or she grows.