Genetic testing for ankylosing spondylitis is getting closer to a successful discovery regarding the link of a specific gene to inflammatory rheumatic disease. The researchers conducted a study focusing on the genetic involvement in the development of the disease. It has been found out that a natural variation of enzymes in the immune system can make a person more susceptible to having an inflammatory rheumatic disease called ankylosing spondylitis.
What is ankylosing spondylitis
An ankylosing spondylitis is a type of chronic inflammatory arthritis affecting the joints in the spine. The pelvic bone (hip) called the ilium and the base of the spine called the sacrum fuse together in order to form the sacroiliac joint which is the one primarily involved in ankylosing spondylitis. The sacroiliac joint becomes inflamed, resulting to a condition called sacroilitis. When the inflammation begins to spread to involve the joints of the vertebra, spondylitis occurs. Ankylosing spondylitis also affects the other joints in the body. This includes the joints of the shoulders, hips, and the knees. In certain cases it can also involve the joints of the spine and ribs.
The genetic involvement in ankylosing spondylitis
Clinical researchers believe that the disease is due to the combination of genetic and environmental causes. The majority of these causes have not been clearly identified. There are certain genes, however, that were identified to cause a greater risk of having the disorder. The gene HLA-B is known to give instructions on certain proteins that are responsible for playing an important role in the immune system that helps distinguish foreign invaders like bacteria and viruses. The HLA-B has another variation called the HLA-B27 which was suspected to be linked to the risk of having the disorder. Its association to ankylosing spondylitis remains unclear, however. Other genes that are believed to increase the risk for the disorder are ERAP1, IL1A, and IL23R. All these play an important role in the immune system but their variations have been suspected to be associated with ankylosing spondylitis as well.
Genetic testing underway
A current genetic testing is getting closer to finding the association of certain types of genes to ankylosing spondylitis, more specifically the ERAP1. As published in the Proceedings of the National Academy of Sciences, UK researchers found different variants of ERAP1 among individuals affected by ankylosing spondylitis. The researchers believe that a better understanding about this gene can help identify the risk factors and prognosis in ankylosing spondylitis through the conduct of a genetic testing.
The disease usually develops at a younger age, usually between 20 and 30 years old and it is thrice as common among males as females. Because there is no cure for the disease, an early diagnosis and preventive measures can help prevent the potential risk of having the disease. The treatment approach is mainly designed to help alleviate the pain and other symptoms. With early detection through genetic testing, there is a greater chance of slowing down its progression and prevent other potential complications.
The ERAP gene
The researchers found out that certain natural variations of the ERAP1 gene can increase the chance of having ankylosing spondylitis as it changes its enzymic function. Among the important function of ERAP1 is to help the proteins become recognizable by the immune system by cutting them down into proteins. Once the ERAP1 fails to accomplish this task, the immune system will identify the proteins as foreign invaders and will attack it to produce the symptoms of ankylosing spondylitis. The research study was able to identify 13 variants of the ERAP1 genes and certain pairs were found to be present among those with ankylosing spondylitis.
As further research is currently underway, the researchers are hopeful to discover how these genes may predispose someone to the disease in order to formulate better preventive measures against the disease.