Is multiple sclerosis hereditary? Genetic and environmental factors play a role

Multiple sclerosis is an autoimmune disease where, for reasons scientists are still trying to figure out, your body’s immune system suddenly attacks the lining covering the nerves in your brain and spinal cord.

“If you think of nerve cells as wires, myelin is like the insulation protecting those wires,” explains Josef Gutman, MD, neurologist and director of the NYU Long Island Comprehensive Multiple Sclerosis Center. Inflammation and other immune damage to the outer lining of nerves can disrupt nerve cell firing, leading to a wide range of symptoms from muscle weakness to vision problems.

Scientists have not found a real cause behind multiple sclerosis. But what is known is that there is a genetic factor that could influence your risk of disease.

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How do your genes affect multiple sclerosis?

There is no single gene that directly causes MS

There are many genes, as many as 233– that everyone has their own small contribution to multiple sclerosis. “There’s a lot of research going into alleles, bits of gene, in people with multiple sclerosis that aren’t seen in the general population that might make them susceptible to the disease,” he adds. Mary Ann Picone, MD., a multiple sclerosis neurologist at Holy Name Medical Center.

Dr. Gutman says those most relevant to the development of multiple sclerosis are those involved in the regulation of the immune system. In other words, genes that regulate what your immune system will or will not target. In effect, to research shows that some of these genes, HLA-DRB1 and HLA-DRB1*15:01, are involved in innate immunity, the first line of defense when a threat is present in the organism, and contribute to the progression of multiple sclerosis.

Your genes play a small role in multiple sclerosis

Having a family history of multiple sclerosis can also increase your risk of contracting the disease, although it is not something that is passed down from parent to child. Also, even if a parent has multiple sclerosis, Dr. Gutman says the increased risk is very small in the grand scheme of things. “Compare it to sickle cell anemia where if one parent has sickle cell disease you have a 25% chance of being a carrier, sometimes 50% depending on the other parent.”

“That’s one of the ways we know multiple sclerosis is an autoimmune disease unlike Alzheimer’s disease, where it’s more of a neurodegenerative disease with a weaker genetic link,” adds Sharon Stoll, DO., a neurologist specializing in multiple sclerosis and neuroimmunology at the Yale School of Medicine.

What is your genetic risk?

You have an estimate 1 in 67 chance (1.5%) of contracting multiple sclerosis if the mother or father also have it. A sibling with multiple sclerosis translates to a 1 in 37 (2.7%) chance of developing it yourself.

In identical twins whose genes are 100% identical, if one has developed multiple sclerosis, the chances of the other getting it are 25%. “If it were a strictly genetic condition, a condition in one twin would mean a 100% chance of getting it in the other,” says Dr. Gutman.

To put it into perspective, Dr. Gutman says that having multiple sclerosis in a close relative makes you 20 times higher than the general population, increasing your overall risk to 2% and 98% chances that you will never develop it. “Again, there is a genetic contribution, but by far the greatest risk is non-genetic.”

Other MS risk factors

Genetics is only part of the story. There are environmental triggers that can increase your risk for multiple sclerosis. These include:

  • Epstein-Barr infection
  • Low levels of vitamin D
  • Age
  • To be female
  • Have other autoimmune diseases
  • Smoking
  • Obesity

How to treat multiple sclerosis?

Experts agree that you should see your primary care physician (PCP) if you experience pain or unusual body sensations. Your PCP can assess symptoms associated with multiple sclerosis such as muscle weakness, numbness in the body, vision problems, and refer you to a neurologist for further testing.

Although Dr. Gutman says that people with family members who have multiple sclerosis don’t need to have routine preventative screening unless you start experiencing disturbing and inexplicable symptoms.

There is no single diagnostic test for multiple sclerosis. Instead, a neurologist may give you several imaging tests, blood tests, and a physical exam to rule out other illnesses. Dr. Stoll says that because multiple sclerosis has a genetic component, you’ll likely be asked if you have a family history of autoimmune diseases or a personal history of autoimmune diseases.

Dr. Picone says there are over 20 FDA-approved treatments for multiple sclerosis, and the earlier you start, the better your chances of getting a good result. If you’re officially diagnosed with multiple sclerosis, Dr. Stoll says your doctor will likely prescribe immunosuppressive drugs to partially suppress the immune system to prevent further damage to myelin. The second drug option are immunomodulators which manipulate immune function and how they respond to a potential threat. Other treatments may involve injectable medications, oral therapies, and other intravenous therapies.

“These are very effective and can go a long way in preventing relapses, slowing progression, and helping you live as normal a life as possible,” says Dr. Picone.