When Genes and the Environment Collide

What happens when genes and the environment interact? This question is one of the complex pieces of the MS puzzle. More than 200 MS susceptibility genes have been identified, and the list of environmental factors linked to MS is slowly coming into focus. Of course, it’s important to remember that not everyone who develops MS has been exposed to the identified MS risk factors, and people exposed to those factors won’t necessarily develop MS. But how do genetic and environmental triggers interact to bring on MS, or make it worse? Several presentations at last week’s ACTRIMS 2017 meeting addressed these important gaps in our knowledge.

Smoking has been singled out as a risk factor for getting MS and has been linked to disease progression. Dr. Thomas Olsson of the Karolinska Institute in Sweden studied whether there was any connection between smoking and the HLA genes (which are involved in immune reactions) that have long been associated with MS. In fact, his team reported a 13-fold increase in risk of developing MS if smokers carried a specific  gene (HLA-DRB1*15 gene) and lacked another (HLA-A*02 gene), compared with people who never smoked and did not have these genetic characteristics (Abstract).

Another study pinpointed a virus that seems to be associated with MS progression. Dr. Antonina Dolei of Universit√† degli Studi di Sassari in Italy talked about studies on human “endogenous retroviruses,” which at some point in the ancient past took up residence in our genes. In fact, she described these retroviruses as “aliens inside human DNA” that might be involved in triggering MS or its relapses. Results so far suggest that the DNA of people with MS has more ‘copies’ of these viruses than people without MS. Finding signs of the viruses in spinal fluid predicted progression years in advance. If such studies are confirmed, these retroviruses may actually be used to help track MS progression, now wholly unpredictable. (Abstract #S4.1)

Both genetics and environmental studies require a lot of people with MS to provide samples and data. The large numbers required make collaboration among doctors and scientists key. One example of big collaborations is the large-scale “Genes & Environment in MS” (GEMS) study, in which researchers at Harvard, University of Pittsburgh, Columbia and the National Institutes of Health are analyzing the genes and backgrounds of individuals who have not reported symptoms of MS, but who have close family members with MS.

Young investigator Dr. Zongqi Xia of the University of Pittsburgh presented results from this ongoing effort. The team classified participants using the Genetic an experimental approach that incorporates genetic information and environmental exposures to identify people at higher or lower risk of developing MS. The study confirmed that people who were labeled “high-risk” were more likely to have imaging findings and vibration insensitivity that might be suggestive of MS. However, in a recent publication from this study, lead scientist Dr. Phillip De Jager pointed out that “family members should be reassured that the vast majority of family members will not develop MS.” (Abstract #S1.8) Read more about this study.

As someone who cares deeply for people affected by MS, I am heartened at this important work by scientists and doctors around the world working to simplify the genetic and environmental complexities that lead to the development of MS and its progression. If we know how genes and potential environmental triggers interact to give rise to the disease or impact the severity of symptoms, we can hopefully better anticipate its course, stop it in its tracks and even find ways to prevent MS.

See what my colleague, Elisabeth Mari, had to say about about research highlights related to vitamin D and gut bacteria here
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Douglas

Douglas Landsman, PhD

Dr. Douglas Landsman is Associate Vice President, Biomedical Research at the National MS Society. He leads the biomedical research and fellowship/faculty award programs, and plays a key role in the International Progressive MS Alliance. He has a long-standing interest in nerve-muscle interaction and developing strategies for promoting nervous system repair after disease or injury.

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    13 Comments

  • Regina Quinn   Mar 1, 2017 4:40 PM
    Thank you for sharing this information with us. Since some of the environmental factors are all that we can control, this information is so very helpful to us. Thank you!
  • John Sweeney   Mar 16, 2017 8:45 AM
    I am from a family of 3 brothers and 2 parents my mother who is 89 was diagnosed when she was in her 60's remit/relapse i was diagnosed remit/relapse at 40 im now 52 and my brother 58 diagnosed progressive ms.growing up neighbors sewer leatched into our well water any correlations
    Thank you john sweeney
  • Judith Alcott Huff   Mar 16, 2017 11:16 AM
    I feel a need to relate the following as it is a unique and intriguing story. Diagnosed in 1978 at the age of 28 through retrobulbar neuritis, I was unaware of genetics and environment/chemical exposure playing a role in ms; age and research have since educated me on the connection. As a teen, I had had exposure to chemicals benzene and toluene and was diagnosed with severe anemia at age 17. At age 22 I was bothered by severe numbness and tingling in my toes and fingers but paid no attention to these symptoms as I was young and healthy. Then came the neuritis which was diagnosed through my ophthalmologist. So, fast forward to this year when I was shocked to read that author Louisa May Alcott, an ancestor (first cousin, 4 times removed), had symptoms identical to mine and that she had been exposed to mercury. Some speculate she had lupus because of a rash she noted but I have also have had rashes and itching during the course of my disease. So, I wonder. Perhaps this a a very good example of genetics and chemical exposure playing a role in ms. Food for thought.
  • Paula Watson   Mar 16, 2017 12:50 PM
    My son was diagnosed with R&R MS several years ago. There is no known history of this in family. Is the gene study ongoing at University of Pittsburgh - and if so, how might I be included in this study???
  • JackieJ   Mar 16, 2017 1:17 PM
    I have 2 other cousins born Jan 1956 Feb 1956 and me march 1956.All have MRI for MS health issues Jan passed away all grew up in IN. I have relapsing and other cousin docs do not go any further in diagnosing and she will not write about it.We have a genetic vit d defiency thruught the family...so bad my sister cant even take shots.For the longes time attributed my good health to staying on top of the D issue.Now struggling searching for ways to cope, but relatives are the worst on looking good means you are....ignoring really whats going on.I fear the future but do live today.Best wishes...genetics......
  • Cecelia J Lauerman   Mar 16, 2017 1:26 PM
    I am a former smoker who believes it was the trigger that developed my MS. I am the only family member with this and the only one who smoked in my younger years including 5 months beginning pregnancy. I also have a daughter now she now has an autoimmune disease that so far is undiagnosed.
  • Dellise H.   Mar 16, 2017 1:38 PM
    This was sent to Elizabeth Mari as well....

    Thank you so much for relaying this most beneficial and enlightening information. It is very encouraging to know the outcomes and paths of research being conducted in this area. I will continue to look for updates. I am very interested in finding out more information on how possible external viruses possibly contracted through sub-dermal penetration... if that makes sense... can in some way be a contributing factor to the development of or onset of MS symptoms. My belief is that a bacteria or virus - parasite possibly - may cause the disease is some cases. Any thoughts would be hugely appreciated. Thank you
  • Brigit Miller   Mar 16, 2017 2:30 PM
    Thank you, very interesting. My neighbor when I was a child about my age and we lived back to back to wetlands. She and I both were diagnosed with MS around the same time, early 40s. I always wonder?
  • Diane von Hardenberg   Mar 16, 2017 6:16 PM
    The interplay of genetics and environmental factors opens so many possibilities as to causation of disease. For older people diagnosed in their 50's, the concept of environmental factors seems more important. Exposure to elements in the environment such as radon in well water, lead in paint, asbestos, and the list goes on. What interests me is when and what causes the breakdown in the immune system that finally manifests the disease. Although my parents did not have MS, each had at least one autoimmune disease. The genetic research is giving us so much good information and coupled with a patient history of environmental exposes opens so many doors as to possible causes of MS.
  • Patti Klein   Mar 16, 2017 6:58 PM
    Is there anyone conducting research on herpes or shingles virus in the trigeminal nerve and development of MS. Thx
  • Nancy Wesenberg   Mar 17, 2017 12:00 AM
    I was dx'd with relapsing/ remitting in 2013, at age 50. I smoked from age 15-24. I was a nurse and exposed to all kinds of things, drugs, formaldehyde, chemos. I lived in Az for 9 yrs which is where I had my first attack but wasn't worked up. I do however have EBV. I'm curious about the stages of ebv. I've gone from an active nurse to a very tired person, bad eyesight.. they made me retire. That's been the hardest pill to swallow.i still cry about my job. I have also gotten shingles, interesting enough down my worst numb painful leg. I'm the fifth person on maternal side with this. My sister as well. I had my boys ages 20 and 24 get a Vitamin d level. One came back at 16 and the other 19. Mine was low too before I started on 10,000ius. Now I wonder if my boys will have it. I would love to be studied, especially what stage of EBV I have. I decided to donate my body to science to study MS and if all the viruses and chemicals I was exposed to. Thank you.i would love to be in some studies.
  • pattymac1223  Mar 17, 2017 5:32 AM
    I was diagnosed at age 64, but have had symptoms for 30 or more years before diagnosis. My mother, her sister, and a paternal cousin all had MS. I grew up in Nebraska, never drank milk as a child, was not obese, but smoked for 30 years.
  • Linda O'Nan, Community Ambassador MSAA Chat Room   Mar 18, 2017 10:24 PM
    Finding out the environmental and biological factors that can predetermine or cause MS, that your multitude of scientists and doctors are working on is one of common discussion in our MSAA Chat Room. We often have new members wanting knowledge about cures for MS. Many of the older members tried to explain to them that when we can figure out what causes MS, we can cure MS. Your research about environmental factors, gut bacteria, and even retroviruses, which I have never heard of before, are truly inspiring and will creates great hope and excitement in our chat room.

    I, for one, would be extremely interested in providing genetic or other information that would aid your doctors and researchers in their investigational studies and research. If trial or donation sites are set up in different areas of the country, please let me know. I am intetested in aiding in any research that might benefit from any information I can provide. Then I will copy the entire article to our MSAA Chat Room. Thanks! Together, we are stronger! And we will continue to pray that you will someday soon make miracles happen!