Hypothyroidism and Down Syndrome

On the health check list every child with Down Syndrome should have in their medical record is yearly screening for thyroid disease.  People with Down Syndrome are at an increased risk of developing hypothyroidism.  Hypothyroidism is a common disorder that can affect all ages, and is found in 1 in 4000 people.  The incidence is higher for people with Down Syndrome.  Anywhere from 13 to 55 % of people with Down Syndrome will develop hypothyroidism over the course of their lifetime.  The good news is that hypothyroidism can be easily treated with medication.


What is a thyroid?

The thyroid is a small gland located below the skin and muscles at the front of the neck, just at the spot where a bow tie would rest. It's brownish red, with left and right halves (called lobes) that look like a butterfly's wings. It's light like a butterfly, too, and usually weighs less than an ounce.

As small as it is, though, the thyroid has an enormously important job to do, especially for teens. It manufactures the hormones that help control metabolism and growth. To do its job, the thyroid needs a chemical element called iodine that the body absorbs from the foods you eat and the water you drink. The entire body contains about 50 milligrams of iodine. About 1/5 to 1/3 of that supply (10 to 15 milligrams) is stored in your thyroid. The thyroid combines the iodine with tyrosine (an essential amino acid) to make important hormones.

Thyroid hormones are released from the gland and travel through the bloodstream to your body's cells. They help control the growth and the structure of bones, sexual development (puberty), and many other body functions. By helping your cells convert oxygen and calories into the energy they need to work properly, these hormones are important in determining if your body will mature as it should. Thyroid hormones also directly affect how most of your organs function. So if your thyroid isn't operating properly, you can have problems in lots of other parts of your body.

What is Hypothyroidism?

This is the state of not making enough thyroid hormone, and is the most common thyroid problem associated with DS. This can be present at birth (congenital) or may occur at any age (acquired). Every state in the US and many other countries routine screen all newborns for hypothyroidism. In newborns and infants with DS, the most common reason for hypothyroidism is that the thyroid did not form correctly in the fetus. In acquired hypothyroidism, the most common reasons in toddlers and older children with DS is (1) autoimmunity (where the body makes antibodies against its own thyroid) and (2) thyroiditis, where the thyroid tissue becomes replaced with white blood cells and fibrous tissue (Hashimoto thyroiditis).

The symptoms of low thyroid hormone are difficult to pick up, especially in infants. They include decreased growth, decreased development, an enlarged tongue, decreased muscle tone, dry skin and constipation -- all of which might be expected in an infant with DS. So, it is recommended that all infants with DS be checked at birth, 6 months of age, 1 year of age, and once a year thereafter for thyroid function, regardless of their growth.

As a parent, what should you do?

Talk to your pediatrician.  Take the health check list to your child's physician.  Get your child screened regularly for thyroid disease.

Be gentle.