Hyperthyroidism occurs when the thyroid gland is overactive and makes too much thyroid hormone. Some people have a genetic predisposition to hyperthyroidism. It is more common in older people and females.

Around 1 in 100 people in the United States over 12 years have hyperthyroidism.

The thyroid gland is an organ in the neck. It produces the thyroid hormones thyroxine (T4) and triiodothyronine (T3). After synthesizing them, it releases these hormones into the blood.

People with hyperthyroidism produce too much T4 and T3 hormone.

This article discusses the genetics of hyperthyroidism. It describes hyperthyroidism and its genetic component, causes, and risk factors. The article also details the symptoms, treatment, and complications of hyperthyroidism.

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A 2018 study explains that genetic factors can make many thyroid issues, including hyperthyroidism, more likely. There is good scientific evidence that hyperthyroidism has an important genetic component.

Many cases of hyperthyroidism arise because an individual has a mutation in one or more genes. These mutations alter typical thyroid function, causing it to produce too much T4 and T3. It is not exactly clear why these genetic mutations arise.

Scientists are continuing to discover the mutations that can lead to hyperthyroidism. A 2021 study lists some genes that may play a role in hyperthyroidism. These include:

  • HLA
  • CTLA4
  • FCRL3
  • TSHR

The same study notes that genetic factors might account for 79% of an individual’s predisposition to develop Graves’ disease. Graves’ disease is a very common cause of hyperthyroidism.

Learn more about Graves’ disease.

Thyroid hormones have several roles within the body. This means that hyperthyroidism causes many different symptoms. According to a 2022 article, some common hyperthyroidism symptoms include:

Several of these symptoms arise as increasing T3 and T4 levels increase metabolic activity.

Learn how hyperthyroidism symptoms vary in males and females.

There are many possible causes of hyperthyroidism. They include:

  • thyroiditis, which is inflammation of the thyroid gland
  • iodine overexposure
  • excess thyroid hormone medication, which doctors prescribe for hypothyroidism — an underactive thyroid
  • other medications, such as lithium and amiodarone
  • a noncancerous tumor on the pituitary gland

Some health conditions can also lead to hyperthyroidism. For example, Graves’ disease and toxic nodular goiter are common causes of hyperthyroidism.

Hyperthyroidism can affect anyone who has a functioning thyroid gland. However, some risk factors make the condition more likely to develop.

The condition is more common in females and people over 60. Other risk factors include:

Research suggests that pregnant individuals have an increased risk of developing hyperthyroidism. According to the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK), severe, untreated hyperthyroidism during pregnancy can affect the pregnant person and the fetus. Mild cases during pregnancy are usually not an issue.

People with hyperthyroidism who are pregnant or planning to become pregnant should talk with a doctor about managing their condition.

Learn more about hyperthyroidism in pregnancy.

Doctors treat hyperthyroidism by managing its symptoms and by attempting to cure its underlying cause.

First-line treatment is usually a beta-blocker such as atenolol (Tenormin). Other treatment options include calcium channel blockers such as verapamil (Verelan/Calan) if a person can not tolerate a beta-blocker.

Doctors may recommend the following methods to treat the underlying cause of hyperthyroidism:

A specific treatment plan will depend on an individual’s symptoms and the underlying cause of their hyperthyroidism.

Hyperthyroidism can cause complications, some of which can be serious. As a 2019 paper explains, hyperthyroidism can lead to cardiovascular issues, including:

  • atrial arrhythmia, where the upper chambers of the heart, or atria, beat out of rhythm with the lower chambers, or ventricles
  • ventricular arrhythmia, where the ventricles do not pump blood efficiently
  • atherosclerotic vascular disease
  • heart failure
  • stroke
  • Graves’ ophthalmopathy, an eye disease
  • osteoporosis and muscle issues
  • menstrual cycle and fertility issues

Thyroid storm

Without treatment, hyperthyroidism can develop into thyroid storm, a life threatening form of hyperthyroidism. There are many possible reasons why hyperthyroidism can become thyroid storm. These include:

  • thyroid surgery
  • infections
  • diabetes
  • cardiovascular disease
  • stroke
  • burns

Some people also develop thyroid storm because they abruptly stop taking antithyroid medication. This medication functions to suppress thyroid activity.

Learn more about thyroid storm.

Anyone concerned about hyperthyroidism should speak with a doctor. This is especially important for people at an increased risk of hyperthyroidism.

If someone’s hyperthyroidism symptoms suddenly worsen, they should seek immediate medical attention. A sudden worsening of symptoms could indicate the beginning of thyroid storm.

The outlook for people with hyperthyroidism is fairly positive, and treatment can successfully manage the symptoms.

If a person does not receive treatment, the condition could develop into thyroid storm, putting a person’s life at risk. Experts suggest that the mortality rate from thyroid storm could be as high as 25%.

Hyperthyroidism is a potentially serious condition with a strong genetic component.

People with hyperthyroidism have an overactive thyroid gland that produces too much thyroid hormone. It causes symptoms such as goiter, heart palpitations, and shortness of breath.

Pregnant people have an increased risk of hyperthyroidism and should work with a doctor to manage the condition during pregnancy.

Treatments for hyperthyroidism are effective and can prevent the condition from leading to complications, such as thyroid storm.