Rheumatoid Arthritis Genetic Discoveries
I got a link to a short interview called GeneTalk with 23andMe: Rheumatoid Arthritis with a key researcher on RA and genetics. Even though it was just an overview, the topics were fascinating. Free sign up may be required to read the full article, but I’ll quote it directly here.
Are there genes that bring a risk for Rheumatoid Arthritis?
Excerpt: “23andMe spoke with Peter K. Gregersen, M.D. about the complex interaction between genes and environment—and how this may affect a person’s risk of developing RA. Over the past decade, Dr. Gregersen has directed the world’s largest effort to identify the genes underlying RA, and he is internationally recognized as a leading investigator in the genetics of autoimmune disorders. In 2004, Dr. Gregersen and his colleagues identified PTPN22 as the first major gene that confers risk for multiple autoimmune diseases—a discovery that provided direct evidence that diverse forms of autoimmune disease are related genetically. Definitive evidence for the existence of additional risk genes for RA emerged from Dr. Gregersen’s laboratory in the last few years.”
What’s interesting here?
We are living in an exciting time. Of course patients want to see research for a cure for Rheumatoid Arthritis. However, the mystery and complexity of the Rheumatoid Arthritis disease process make that a more difficult prospect than most of us can fathom. That is why we ought to be keeping our eyes on genetic research that could provide clues about how RA works.
How much do genes increase Rheumatoid Arthritis risk?
Excerpt: “Dr. Gregersen: There is a genetic component to rheumatoid arthritis, and we know this because of a slight tendency for RA to cluster in families. For example, the risk to an identical twin of someone with RA is increased about 20-30 fold, and siblings are at about 3-10 fold increased risk. However, because RA is not that common in the population (~0.5% or 1 in 200 people), the absolute risk to siblings is still fairly low. There are clearly other environmental factors, such as smoking, that also increase risk for RA. We don’t yet have a full understanding how genes and environment interact to cause this disease. We have known for over two decades about a group of genes on chromosome 6 called HLA genes that carry a moderate risk for developing RA.”
What’s interesting to us?
Articles vary in reporting prevalence of Rheumatoid Arthritis. Recent studies found RA to be more common than previously believed. It’s shocking how much we don’t know. Look at the range for risk of siblings: between three and ten times the risk? Not odds you could use to bet.
An explosive period of discovery for Rheumatoid Arthritis
Excerpt: “In most cases, we haven’t yet really established what the specific variation is that actually causes the increase in risk. We are currently in an explosive period of discovery, and I expect that a number of additional genes associated with RA will be discovered in the coming year or two. …It is interesting, however, that recent data suggests that the combination of cigarette smoking and having some of the riskier versions of genes associated with RA may put someone at quite high risk for some types of RA. This is particularly evident for a type of RA that is accompanied by antibodies to proteins that have been modified to contain the amino acid citrulline.”
There are “riskier versions of genes”? There are “some types of RA”? These are not things that we learn from our rheum docs so I was glad to read this. A recent blog discussed the “citrulline” component to RA research.
Can gene risk be used to help people with Rheumatoid Arthritis?
Excerpt: “At this point, there are no clinically actionable steps that can be recommended based on a person’s genetic profile at these RA risk alleles. Despite the lack of immediate practical benefit for patients and families, I believe the coming discoveries in genetics are going to ultimately give us a much clearer picture of what is causing RA, which will allow us to diagnose and treat the disease much more effectively. There is also a big push on now to use both genes as well as other types of laboratory tests (such as antibodies and other blood measurements) to properly select drugs for people with RA.”
So, genetic tests could confirm RA diagnosis or disease severity
It’s not here yet, but genetic tests may be a key to earlier and more effective Rheumatoid Arthritis treatment. The things we discuss here on this site about (1) treatment that is as aggressive as appropriate for each the patient, (2) early examinations with rheumatology specialists, and (3) relying on more heavily upon patient measures of disease activity will all make more sense when there are medical tests that can confirm disease activity. However, those three principles will remain essential in order to obtain the tests.
Listen to Dr. Gregersen talk about genetic research for RA here on video.
Postblog: Indeed there are several new studies this year on genetics and Rheumatoid Arthritis. We cannot review them all here, but here is a link to another about predicting erosive Rheumatoid Arthritis disease / inflammatory polyarthritis.
- The Future: Predicting Rheumatoid Arthritis Severity
- 21 Things to Know About Finding a New Rheumatologist / Rheumatoid Arthritis Specialist
- 20 Questions RA Patients Should Ask a Doctor
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