Ankylosing spondylitis is a form of arthritis that primarily impacts your spine, causing inflammation and reducing mobility in the surrounding joints. It may run in families.

Ankylosing spondylitis (AS) affects about 1 in 200 people, according to a 2021 research review.

While anyone may develop AS, it usually develops before the age of 45 and is thought to run in families. People with certain autoimmune diseases may have a higher likelihood for developing it.

If you have a family history of AS, or are curious about whether you may carry certain genes that increase your risk, read on to learn more about these connections and when you might consider contacting a doctor.

Inflammation within the joints and ligaments in your spine causes AS. Over time, chronic inflammation can cause the bones of your spine to grow together, leading to inflexibility and reduced mobility as well as possible bone fractures.

While the precise cause of AS isn’t known, it’s thought that a combination of genetics and environmental factors may play a role in its development.

In fact, if someone in your family has AS, you’re considered to have a greater risk of developing this condition at some point.

Since AS may run in families, researchers are looking at genetic markers that may provide clues about whether certain people may be at risk of developing this type of arthritis.

The primary gene linked to AS is called the human leukocyte antigen B27 (HLA-B27) gene, which would be inherited from your parents. In fact, it’s believed that more than 80% of people with AS carry it.

However, while carrying HLA-B27 is known to increase the risk of AS, this doesn’t mean you’ll automatically develop it. Overall, it’s thought that between 5% and 10% of children who carry HLA-B27 will develop AS. Many people with this gene never develop AS.

Also, while the HLA-B27 gene is the primary genetic link to AS development, other genes are being looked at for possible causes. These include:

  • ERAP1
  • IL1A
  • IL23R

While carrying the HLA-B27 gene isn’t definitively connected with AS development, there’s still a known risk between the two. If AS runs in your family, you might consider undergoing genetic testing to better understand your own risk factors.

According to one 2021 clinical review, there’s an average delay of AS diagnosis by as much as 6 to 10 years. This further highlights the importance of genetic testing, especially if you suspect the condition runs in your family.

Additionally, since there’s a 50% chance you may pass on the HLA-B27 gene yourself, gaining confirmation via genetic testing can provide peace of mind.

Genetic testing for HLA-B27 comes in the form of a blood test that looks for changes in your DNA. Before seeking such a test, a doctor may refer you to a genetic counselor. They will go over your health and family history and determine whether testing is right for you.

Testing for the HLA-B27 gene can help determine your overall AS risk, but a doctor will likely run other tests to help diagnose this condition. These include:

  • a physical exam
  • an evaluation of your medical history
  • an imaging test, like an X-ray or MRI

Aside from the HLA-B27 gene and overall family medical history, there may be other risk factors for AS. These include preexisting inflammatory conditions, such as:

While age itself isn’t a risk factor for AS, people with this condition may start experiencing symptoms during childhood or early adulthood, between the ages of 15 and 30. Most people receive a diagnosis by their 40s.

Also, while race and ethnicity aren’t direct causes of AS, the condition appears to be more common in Indigenous North Americans, Asians, and Europeans.

AS notably causes stiffness and pain in your back and hips, which may progressively worsen over time. While the condition varies from person to person, other possible symptoms may include:

  • rashes
  • vision problems
  • gastrointestinal discomfort

On a short-term basis, you may notice that you have flare-ups, or when your symptoms may come and go. You might also have worsening pain and stiffness after periods of rest, such as after sitting or after waking up from sleeping.

Prompt treatment to help prevent worsening symptoms and new symptoms is important after receiving an AS diagnosis. Additionally, treatment may help improve your energy levels and ability to move around comfortably throughout your day-to-day activities.

A treatment and management plan may involve a combination of:

Surgery may be another step to consider if the above treatments don’t help. Options might include joint repair or replacement.

Since there’s no cure for AS, early identification is important in starting treatments and other management techniques that may reduce the progression of related spinal problems. If AS runs in your family, you might consider genetic testing to get ahead of this arthritis before symptoms begin.

If you’re experiencing possible symptoms of AS, such as chronic back pain and stiffness, reach out to a doctor for an evaluation. They can help run tests to determine whether you’re experiencing AS or another condition and recommend the right treatments.