Researchers at the University of Texas Medical School at Houston have discovered two genes that cause ankylosing spondylitis (AS), an inflammatory and potentially disabling form of arthritis.
John D. Reveille, M.D., professor and director of the Division of Rheumatology and Clinical Immunogenetics, in collabration with Matthew A. Brown, M.D., professor of immunogenetics at Australia's University of Queensland, led research done by the Triple "A" Spondylitis Consortium Genetic Study.
Reveille said that the discovery of genes ARTS1 and IL23R has brought the scientific community two steps closer to fully understanding AS that attacks the spine and also can target other joints and organs in the body.
"We've long known that the HLA-B27 gene accounts for 40 percent of the overall cause of AS," Nature Genetics quoted Reveille, as saying. "Now we have found two new genes. Together with HLA-B27, these genes account for roughly 70 percent of the overall cause. That means we've almost nailed this disease. Within the next year, I predict we will have identified all the genes that play a role in this insidious disease. There is more exciting news to come," Reveille added.
The latest discovery is based on work from the largest and most comprehensive genome-wide association scan conducted to date. For the study, the authors were searching for genetic information related to AS, as well as autoimmune thyroid disease/Graves' Disease, breast cancer and multiple sclerosis.
Reveille said that the most significant findings were in AS, a disease that generally strikes patients in their teens, 20s or 30s. Reveille said that the identification of ARTS1 and IL23R has shown a new pathway of causation and this could lead to new therapies for the arthritic condition, which can cause a complete fusion of the spine, leaving patients unable to straighten and bend.
The discovery of the two new genes also could help physicians identify patients who are at the highest risk for developing AS. "For example, if you have a family member with AS, a simple blood test would be able to tell us if you are also at risk. We could offer screenings for people with back pain. In the past, the HLA-B27 test was all we had. Now we potentially have more tests," Reveille said.
Steve Haskew, who has lived with AS for thirty years, said the genetic discovery offers hope to patients - especially those who are newly diagnosed. "When I first started experiencing problems - lower back pain, the aching joints - no one could tell me what was wrong," said Haskew, 59, co-leader of an AS support group that meets every other month at the UT Medical School at Houston.
"It took 10 years before a rheumatologist diagnosed me with AS. Back then, there weren't many options. I was told to take anti-inflammatories and stay as active as possible. It's fascinating to see how far we've come and how much has been learned about the disease since then," Haskew added.
"This is a success story for genetics work, and I think it will lead the way for other work to be done," Reveille said. The new study is published in the Oct. 21 online edition of Nature Genetics.