What Is the Link Between Genes and MS?

The role of genetics in MS is complex, and researchers are still working to identify all the genes involved. However, it is clear that genetics plays a role in MS development. Current genetic research may lead to new treatments or even a cure for the disease.1-3

Inheritance

Many doctors tell people with MS that the disease is not hereditary in the true sense of the word. This is because MS is not passed down from parent to child, like some diseases. However, there is an increased risk in people who have a family member with MS. It is not unusual for 2 or more family members to have MS.2

In a study of over 42,000 people in Sweden who had a parent with MS, only 515 had been diagnosed with the disease. This meant there was about a 1 in 80 chance of both the parent and child having MS. There is about a 1 in 400 chance of completely unrelated people both having MS.2

Genes in MS

MS is likely caused by a combination of factors, including genes. No single gene causes MS, but several genes have been identified as risk factors. These genes are often involved in the function of the immune system. Experts think that a person's risk for MS increases if they have a family history of the disease or carry specific genetic variants.1-3

However, just having these genes is not enough to cause MS. Other risk factors must be present to cause MS in someone who has genes that make them more likely to get it.1-3

Other factors

Doctors think MS is caused by many different factors, not just genes. Other factors may include one's environment and previous infections.1-3

Environmental factors

There are several environmental factors that affect risk for MS. These include:1-3

Smoking – Smoking increases the risk of developing MS. Researchers think this is because it causes inflammation in the body.
Obesity – Being very overweight also increases inflammation. This may be the reason it is linked to higher MS risk.
Living in certain areas of the world – Living far from the equator and in northern latitudes increases the risk for MS. This is likely because these regions have less sunlight. Sunlight is needed to produce vitamin D, and low vitamin D levels have been linked to increased risk for MS.

Infections

Certain infections seem to increase people's risk of developing MS. These infections are caused by viruses such as the Epstein-Barr virus (EBV) and the human herpes virus 6 (HHV-6). However, these viruses are common and thus not the sole cause of MS. Experts believe that about 95 percent of adults have had a prior EBV infection. The same is true for HHV-6 infection.3-5

What does this mean for you?

If you are concerned that you may have a family history of MS, the best thing to do is speak with your doctor. They will be able to review your medical history, any family history of the disease, and other factors that might contribute to your risk. Also, they may be able to refer you to a genetic counselor who can help you better understand your risk.1

Putting together the MS cause puzzle

The causes of MS are complex, and there are no clear answers. Genes play a role, but other factors also need to be present. Talk to your doctor about your overall risk, especially if MS runs in your family. The two of you can discuss the risks and weigh the best options for you.1-3

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Written by: Katie Murphy | Last reviewed: June 2022.