Ankylosing spondylitis: What role does the HLA-B27 gene play?

What is ankylosing spondylitis?

Ankylosing spondylitis (AS) is a chronic inflammatory disease that mainly affects the spine and joints. It is characterized by persistent back pain, morning stiffness, and sometimes extra-articular symptoms such as inflammation of the eyes or intestines.

The development of AS is closely linked to genetic factors, among which the HLA-B27 gene plays a central role. Understanding this gene and how it influences the disease helps improve diagnosis and patient care.

The role of the HLA-B27 gene in ankylosing spondylitis

HLA-B27 is a genetic biomarker located on chromosome 6 that plays a role in regulating the immune system. Having this gene significantly increases the risk of developing AS, although not everyone who carries HLA-B27 will develop the condition.

Being HLA-B27 positive simply means the person carries this gene; it does not automatically predict the disease. Researchers believe HLA-B27 may influence the way the immune system responds to bacteria or infections, sometimes triggering chronic inflammation of the spine and joints.

What does it mean to be HLA-B27 positive?

Testing positive for HLA-B27 doesn’t mean a person will definitely develop AS. However, this marker helps identify individuals at higher risk and supports diagnosis when combined with symptoms and imaging findings.

The HLA-B27 test is one of several tools used to confirm genetic predisposition and guide medical follow-up.

Symptoms and diagnosis of AS

Symptoms vary widely from one person to another, but certain early signs are common. Pain and stiffness in the lower back, especially after periods of rest or upon waking, are often the first warning signs.

Other joints, such as the hips, shoulders, or knees, may also be affected. Chronic fatigue and sleep disturbances are frequent and can significantly impact quality of life.

Diagnosis relies on a clinical examination, X-rays, MRI scans, and the HLA-B27 genetic test, which helps assess the likelihood of AS.

Risk factors and heredity

Genetics and family history play a key role in the development of AS. People who have a close relative living with the condition are at greater risk, especially if they also carry the HLA-B27 gene.

However, the disease is not transmitted automatically. Its development depends on an interplay of genetic predisposition and environmental factors. Understanding this genetic dimension helps identify those at risk and encourages early monitoring.

Treatment and management of AS

Managing AS combines medication with non-pharmacological approaches. Anti-inflammatory drugs are often prescribed to reduce pain and inflammation, while physiotherapy helps maintain joint mobility and prevent stiffness.

In more severe cases, targeted biologic therapies may be used to control significant inflammation.

Key Takeaways

• AS is a chronic inflammatory disease mainly affecting the spine and joints, with back pain and morning stiffness as common symptoms.
• The HLA-B27 gene increases the risk of AS, but having it does not mean the disease will definitely occur.
• Being HLA-B27 positive helps identify people at risk and supports diagnosis in combination with symptoms and imaging.
• Symptoms include joint pain, chronic fatigue, sleep issues, and stiffness, requiring diagnosis through clinical examination, imaging, and genetic testing.
• Genetics and family history influence risk, but environmental factors also play a role.
• Treatment combines medication (anti-inflammatories, biologics) with physiotherapy to maintain mobility and limit inflammation.

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