Is Hashimoto's Disease Hereditary?

Hashimoto’s disease, also known as Hashimoto’s thyroiditis, is a chronic autoimmune disease. It’s the most common cause of hypothyroidism in the US¹. Hypothyroidism, where the thyroid gland is underactive and doesn’t produce enough hormone, affects 5%² of Americans.

The thyroid³ is a gland at the front of your neck that produces triiodothyronine (T3) and thyroxine (T4), two hormones that control how fast your body burns energy (metabolic rate) and keep your body working as it should. It works together with the pituitary gland which produces thyroid-stimulating hormone (TSH). Hashimoto’s disease occurs when your immune system mistakenly attacks the thyroid which causes damage over time and eventually results in hypothyroidism.

Many risk factors can increase your chance of developing Hashimoto’s disease, including if the condition runs in your family.

Can Hashimoto’s disease run in your family?

A hereditary disease is a condition that affects members of the same family and is passed down through generations. Hashimoto’s disease is hereditary; it is thought to be caused by a combination of environmental and genetic factors⁴.

Studies⁴ show that people with Hashimoto’s disease tend to have family members who are also affected by the condition. Variants or mutations occurring in the human leukocyte antigen (HLA) complex gene family⁵ are thought to be responsible for many Hashimoto’s disease cases. This gene family helps regulate your immune system and your protection from bacteria and viruses. A variation or mutation among these genes can cause your immune system to mistakenly attack your thyroid.

Although you may be more likely to develop Hashimoto’s disease if it’s in your family medical history, this does not guarantee you will develop the disease yourself.

Other risk factors for developing Hashimoto’s disease

Besides genetics, other risk factors play a role in increasing your chance of developing Hashimoto’s disease, including:

Sex

Women are more likely than men to develop Hashimoto thyroiditis⁶. The reasons for this are still unclear, but researchers believe⁷ Hashimoto’s disease is more likely to occur in women because they have two copies of the X chromosome, one of which gets inactivated, and over time may cause the condition to develop by not being “active” enough.

Another hypothesis is that women have higher immune reactivity⁸ than men, which may increase their risk of developing autoimmune diseases.

Age

Research suggests that women are more likely to develop Hashimoto’s disease between the ages of 30 and 50⁹. The severity of the disease worsens over time as thyroid activity deteriorates, which could make symptoms more noticeable.

Race and ethnicity

Hashimoto’s disease affects more people of Caucasian descent than those of African American and Hispanic descent¹⁰.

Diet

Iodine¹¹, zinc¹², and selenium¹³ are essential for maintaining a healthy, functioning thyroid. You may be more likely to develop Hashimoto’s disease if you are deficient in these minerals.

Pregnancy

Hormone and immune system changes during pregnancy¹⁴ may speed up the development of Hashimoto’s disease and reveal symptoms either during pregnancy or after delivery. Postpartum thyroiditis, another type of thyroiditis not unlike Hashimoto’s, affects 3–8%¹⁵ of women postpartum.

Radiation

Environmental exposure to radiation¹⁴ may increase your risk of developing Hashimoto’s disease; however, the evidence is conflicting.

Hashimoto’s disease symptoms

Make an appointment with your doctor if you experience any of the following symptoms¹⁶:

• Goiter (enlarged thyroid)

• Fatigue

• Hair loss

• Slowed heart rate

• Sensitivity to cold and/or heat

• Cramping or aching muscles

• Constipation

• Unexplained weight gain

• Irregular menstrual cycle

Hashimoto’s disease’s signs and symptoms are not unique, so it might be easy to ignore them or attribute them to something else. Symptoms tend to develop over a long period of time as the disease worsens, but an early diagnosis can help ensure you get the treatment you need to prevent complications.

How is Hashimoto’s disease diagnosed?

Talk to your doctor if Hashimoto’s disease runs in your family, especially if you think you might have symptoms. Your doctor will look at your personal and family medical history and carry out a physical examination.

Typically, if a blood test reveals your TSH levels are abnormal, your doctor will test your T3, T4, and thyroid antibody levels. If your thyroid antibody levels are high and your thyroid hormone levels are low, you may have Hashimoto’s disease.

What treatments are available for Hashimoto’s?

The treatment you undergo for Hashimoto’s disease depends on the cause and severity of the condition. Your doctor can recommend a treatment plan to help manage the condition and ease your symptoms.

Common Hashimoto’s disease treatments include:

Medications

Taking levothyroxine¹⁷ (a synthetic version of the thyroid hormone T4) helps regulate thyroid hormone levels in your body and ease Hashimoto’s symptoms.

Desiccated thyroid (derived from animal thyroid) is another type of medication but it is rarely used.

Alternative treatments

Your doctor might suggest you make some changes to your diet to promote healthy thyroid function and counter mineral deficiencies. For example, they might recommend that you adjust your intake of selenium, iodine, and zinc.

Vitamin D¹⁸ plays an important role in regulating the immune system. Limited research suggests the vitamin may be useful in managing thyroid conditions like Hashimoto’s disease, but more studies are needed.

Supplements may be prescribed to help you get optimal quantities of the nutrients you need, but don’t start taking supplements without speaking to your doctor first.

The lowdown

Hashimoto's thyroiditis is an autoimmune disease, where the autoantibodies (built by your immune system) attack the thyroid and cause inflammation. Untreated, Hashimoto’s disease can cause complications, including hypothyroidism.

Genetics is not the only risk factor for Hashimoto’s disease; other factors like radiation exposure, age, sex, and pregnancy can increase your risk. However, if you know someone in your family who had Hashimoto’s disease or is living with it now, keep an eye out for symptoms like fatigue, unexplained weight gain, and goiter. Speak to your doctor if you have any concerns as early diagnosis and treatment can help prevent complications.