Is Hypothyroidism Genetic? Why Family History Isn’t Everything

is hypothyroidism genetic: Three women smiling and looking at each other

If you have a family member with thyroid problems, the question, “Is hypothyroidism genetic?” may be on your mind. 

Research does suggest that there are genetic reasons for thyroid problems. However, genetic risk is only part of the picture. Diet, environment, stress, and other lifestyle factors can influence how genes express themselves and whether thyroid disease develops. 

In this article, we’ll discuss what’s known about the genetic risks for hypothyroidism and autoimmune thyroid disease. We’ll also cover how you can mitigate these risks through lifestyle modifications that support thyroid health. 

Hypothyroidism Explained

Hypothyroidism (underactive thyroid) occurs when your thyroid gland doesn’t produce enough thyroid hormone, resulting in a thyroid hormone deficiency. The most common symptoms of hypothyroidism include:

  • Weight gain or obesity
  • Feeling cold
  • Fatigue
  • Digestive problems
  • Brittle hair and fingernails
  • Dry skin
  • Poor memory
  • Depression
  • Brain fog and headaches
  • Low sex drive
is hypothyroidism genetic: Tablet on top of a diagnosis sheet surrounded by medical tools

According to the American Thyroid Association, Hashimotot’s thyroiditis (also known as Hashimoto’s disease) is the most common cause of hypothyroidism. Hashimoto’s thyroiditis is an autoimmune condition that causes swelling of the thyroid gland.

Approximately 1%-2% of people in the United States may have Hashimoto’s disease. However, the prevalence in women is 10 times greater than in men (Vanderpump 2011)

Autoimmune thyroiditis results from an immune system attack on the thyroid gland. Symptoms may include thyroid nodules, non-painful goiter, and swelling or pain in the thyroid gland.  

Over time, chronic thyroid inflammation can damage the thyroid gland, resulting in low thyroid function. However, not all cases of autoimmune thyroiditis progress to hypothyroidism. 

Is Hypothyroidism Genetic?

It’s not uncommon for patients with hypothyroidism to have family members who are also hypothyroid. So, it’s not surprising that “Is hypothyroidism genetic?” is a common question we hear.

Research suggests that there is a genetic link: 

  • Having first-degree family member (mother, daughter, aunt) with a thyroid problem is an increased risk factor for developing a thyroid disorder (Vaidya et al. 2002).

More specifically, genetic sequencing tests have identified candidate genes that may increase a patient’s risk of autoimmune thyroid disease.

Genetics and Autoimmune Hypothyroidism

is hypothyroidism genetic: 3D illustration of a DNA molecule

While research into the genetic links to autoimmune thyroid disease is not yet conclusive, here’s what’s been learned so far:

While having a family history of Hashimoto’s thyroiditis may increase your risk for autoimmune thyroid disease, you can positively influence your genetic expression. In other words, your lifestyle plays a significant role in triggering or suppressing these genes. 

In a moment, we’ll dig more into epigenetics, the study of how your behaviors and environment can affect the way your genes work.

Genetics and Congenital Hypothyroidism

Congenital hypothyroidism is a rare form of hypothyroidism that is present at birth. Congenital hypothyroidism results in partial or complete loss of thyroid gland function and an impaired ability to produce thyroid hormones (Peters et al. 2018). This loss of function (thyroid dysgenesis) means the thyroid gland is absent, abnormally located, or reduced in size.  

Less common causes of congenital hypothyroidism include disruptions in the hormone synthesis process (thyroid dyshormonogenesis) or an abnormality in the pituitary gland (central hypothyroidism).

Some researchers have concluded that gene abnormalities are associated with fewer than 5% of congenital hypothyroidism cases (Sindhuja et al. 2016). However, one study of children with congenital hypothyroidism caused by thyroid dysgenesis (missing or underdeveloped thyroid gland) found that almost 72% of them had first-degree relatives with thyroid disorders (Castanet et al. 2000). This suggests that the genetic link for congenital hypothyroidism may be much stronger than 5%.

Epigenetics and Thyroid Disease

The field of epigenetics studies how our environment and behaviors influence our gene expression. The genes we inherit creates susceptibility to certain diseases. However, our lifestyle (physical activity, nutrition, stress, alcohol, and drug consumption) may have a greater influence than our genes.

Environmental triggers and lifestyle factors that influence thyroid gene expression include specific foods (Feil and Fraga 2012) , toxin exposure (Patrick 2009), and a patient’s iodine status (Ban and Tomer 2005)

Another common environmental trigger for thyroid disease is an imbalance in the gut microbiome. Western diets, antibiotic exposure, overuse of antibacterial products, and other modern lifestyle practices can adversely impact the gut ecology and immune system health. For those with genetic susceptibility, this can lead to thyroid disease. 

A comprehensive thyroid treatment plan should address factors that improve gut health. This includes attention to diet and lifestyle and taking probiotic supplements. Some patients will need to take further steps to diagnose and treat bacterial and fungal gut infections. In the next section, we’ll describe a step-by-step plan for improving thyroid health.

For a comprehensive review of the gut-thyroid connection, download our gut-thyroid guide.

Thyroid Treatment Plan

If you’ve been diagnosed with hypothyroidism, levothyroxine (thyroid hormone replacement medication) is an effective treatment for bringing thyroid hormone levels back to normal ranges. 

However, many thyroid patients don’t feel well, even when taking thyroid medication. This may be especially true for patients with Hashimoto’s disease. While thyroid hormone replacement does effectively restore thyroid hormone levels, it does not remove the triggers that cause immune system dysfunction and autoimmunity.

Steps for Hashimoto's health chart by Dr. Ruscio

A multi-step approach to improving thyroid and overall health includes the following:

  1. Take a standard thyroid hormone replacement, such as Synthroid, to get your thyroid hormone levels in range.
  2. Make fundamental lifestyle improvements, such as reducing stress, getting 7-9 hours of quality sleep each night, and including some physical activity in your daily routine.
  3. Eat an anti-inflammatory diet and identify foods that trigger your symptoms.
  4. Take probiotics to help restore balance to your gut ecosystem.
  5. Take supplements to treat deficiencies in iron, vitamin B12, vitamin D, and zinc. Selenium has been shown to reduce TPO antibodies in autoimmune thyroiditis (Toulis et al. 2010) (Fan et al. 2014) (Wichman et al. 2016). Take 200 mcg for 6-12 months and then discontinue.
  6. Treat gut infections that may be contributing to immune system dysfunction. A functional medicine practitioner can help you diagnose and treat gut infections.
  7. Adjust thyroid medication, if necessary. In some cases, thyroid medication is better absorbed once significant gut healing takes place. Have blood tests to check your thyroid levels periodically and adjust medication, if needed.

Dietary Support for Thyroid Health

Variety of fresh foods on top of a wooden surface

When it comes to eating well for thyroid health, it’s important to eat fresh, unprocessed, and whole foods. For those who want a diet template to follow, the Paleo Diet is a great place to start and can provide a simple framework to support thyroid health. 

Another consideration for thyroid patients is noting the possible food triggers that cause inflammatory symptoms. Research suggests watching for these common triggers:

Not all thyroid patients are sensitive to gluten, dairy and high-carb diets. The best way to determine your own sensitivity is to follow an elimination diet for 2-3 weeks and then reintroduce the food and monitor for reactions.

Thyroid Testing

If you have a family history of thyroid disease, it’s important to monitor your thyroid health through lab testing. Caught early and managed well, a condition like Hashimoto’s thyroiditis does not have to lead to thyroid damage and lifelong hypothyroidism.

The most important thyroid markers to monitor are:

  • TSH (Thyroid-stimulating hormone)
  • Free T4 (thyroxine)
  • TPO (thyroid peroxidase antibodies)

T4 and TSH levels are used to diagnose hypothyroidism and hyperthyroidism. 

Elevated levels of TPO antibodies indicate Hashimoto’s disease. And, as mentioned earlier, Hashimoto’s disease does not always lead to hypothyroidism. 

The Bottom Line

In summary, the answer to “Is hypothyroidism genetic” is both yes and no.

Having genetic susceptibility to thyroid disease does not need to mean a lifelong sentence of hypothyroid symptoms. Your lifestyle choices can tip the scales in your favor, whether to prevent development of thyroid disease or as a way to actively manage a diagnosis you’ve already received.

Making healthy food choices, avoiding environmental triggers and toxins, and making sure your gut is healthy can positively influence your thyroid health. 

If you’re struggling with hypothyroidism or autoimmune thyroid disease, schedule an appointment with one of our practitioners today. 

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