Down syndrome and the thyroid: what families need to know about Hashimoto’s thyroiditis

People with Down syndrome have many strengths, as well as some specific health needs. One of the most important — and sometimes less well known — is the link between Down syndrome and thyroid disorders, particularly Hashimoto’s thyroiditis.

What is Hashimoto’s thyroiditis?

Hashimoto’s thyroiditis is an autoimmune condition. This means that the immune system, which normally protects us from infections, mistakenly attacks the thyroid gland. Over time, the thyroid may slow down and produce fewer hormones, leading to hypothyroidism.

Thyroid hormones are essential because they influence:

• Energy levels and metabolism
• Growth and development
• Attention, memory and mood
• The functioning of the heart, muscles and digestive system

Can women with Down syndrome develop Hashimoto’s?

Yes. Women with Down syndrome can develop Hashimoto’s thyroiditis, and overall people with Down syndrome (both women and men) have a higher risk of autoimmune thyroid disease than the general population.

In addition:

• Hashimoto’s can appear at a younger age
• It does not always follow the typical pattern seen in the general population
• Symptoms may be mild or unclear at first

Why is it more common in people with Down syndrome?

The main reason is related to Down syndrome itself. The presence of an extra copy of chromosome 21 affects how the immune system works and increases the tendency to develop autoimmune conditions, including Hashimoto’s thyroiditis, as well as others such as coeliac disease or type 1 diabetes.

This is not caused by anything families have done or failed to do — it is part of a biological predisposition.

What symptoms should families look out for?

Hypothyroidism may cause symptoms such as:

• Excessive tiredness
• Unexplained weight gain
• Feeling cold
• Dry skin or hair loss
• Constipation
• Changes in mood, concentration or alertness

In people with Down syndrome, some of these signs can be mistaken for features related to the syndrome itself, which means they may go unnoticed.

Why regular monitoring is so important

Medical societies and specialist organisations recommend that people with Down syndrome have regular thyroid checks throughout their lives, even if there are no obvious symptoms.

These checks usually involve a simple blood test (TSH and, in some cases, additional hormones or antibodies).

What happens if Hashimoto’s is diagnosed?

The good news is that:

• Treatment is effective and safe
• In most cases, it involves taking a daily thyroid hormone tablet
• When properly adjusted, treatment improves energy, wellbeing and quality of life

Early diagnosis and treatment of hypothyroidism are especially important to support physical health, development and emotional wellbeing.

A final message for families

• ✅ Yes, women with Down syndrome can develop Hashimoto’s
• ✅ It is more common than in the general population
• ✅ Regular screening allows early detection
• ✅ With appropriate treatment, people can enjoy a full and healthy life

Looking after thyroid health is another way of supporting the potential and quality of life of people with Down syndrome.