Is Multiple Sclerosis Hereditary?

If you have multiple sclerosis (MS) — an autoimmune disease that attacks nerves in the spinal cord, brain, and eyes — you may worry about passing it on to your children. While MS is not hereditary, meaning it’s not directly transmitted from parent to child or passed down in a family through generations, having a first-degree relative with MS does increase the risk of MS.

Among the general population, the odds of developing MS are about 1 in 750 to 1,000, according to the National Multiple Sclerosis Society (NMSS). An identical twin whose sibling has MS, however, has a 1 in 4 or 5 chance of developing MS.

A 2013 analysis of 18 studies found the following lifetime risks of developing MS for family members:

• 1 in 5 if an identical twin has MS
• 1 in 22 if a nonidentical twin has MS
• 1 in 37 if a sibling has MS
• 1 in 67 if a parent has MS

Multiple Sclerosis in MyMSTeam Members’ Families

Some members of MyMSTeam have parents, siblings, or children with MS. “Six people in my family (including myself) have it,” said one member. “I was diagnosed first. Then my sister, who died from complications. Now my niece has it,” shared another.

Other members reported diagnoses on just one side of the family. “My first cousin and my aunt’s granddaughter have it, all on my dad's side,” said one. “A cousin and an aunt, both on my maternal side,” shared another.

Multiple sclerosis may only affect one generation of a family. “All my siblings have it,” said one member. “My oldest sister has been diagnosed. My younger sister and brother have symptoms, but won’t get diagnosed. No one in our family that we know of has it except us. Weird.”

Members with no family history of MS expressed surprise when they — or someone in their clan — received a diagnosis. “We were shocked when my daughter was diagnosed just before her 20th birthday. How could this be? Where did it come from? Then, three years later, I was diagnosed at age 57.”

Which Risk Factors Cause Multiple Sclerosis?

While the cause of MS is unknown, scientists are finding that both environmental and genetic factors play a role. More than 200 genes have been linked to MS, and people with the disease may have one or a combination of genetic factors. The 2013 study calculated that genes contribute to 54 percent of MS risk factors.

With MS, an abnormal immune system response causes inflammation and damage to the central nervous system and myelin sheath protecting nerves. Environmental factors for MS include viruses, infections, smoking, obesity, and geographical location (including the northern U.S., southern Canada, parts of Europe, southern Australia, and New Zealand).

Low vitamin D levels in the blood have also been identified as one of the risk factors for MS, according to the National Multiple Sclerosis Society. Ongoing research and clinical trials are investigating the role of vitamin D supplementation in supporting immune system function, which could protect against immune-related diseases such as MS.

Even though MS is influenced by environmental factors, parents on MyMSTeam still worry about passing the condition to their children. “I’ve got two beautiful daughters whom I don’t ever want to have to deal with this,” one member shared.

Another member suspects stress, rather than heredity, caused his MS. “No one in my family has MS, so I believe mine was caused by stress. MS surfaced after I went through an excessive amount of issues the past five years,” he shared.

Share Family History of MS With Your Doctor

Some MyMSTeam members expressed concern that their doctors didn’t look for MS. “My mom and I have MS. Neither of our neurologists asked for medical histories, where we’ve lived, or run medical tests to understand why two people in the same family developed the same ‘noncontagious, nonhereditary’ disease. I’m completely perplexed,” one member said.

Other members urged their MyMSTeam friends to share complete family histories with doctors. “My brother was having problems with his vision and the doctor couldn’t pinpoint the problem. I asked him, 'Did you tell the doctor your sister has MS?' The answer was no. As soon as he did, they tested him for MS and guess what?” one member explained.

You Are Not Alone: Finding Support for MS in the Family

On MyMSTeam, the social network and online support group for those living with MS, members talk about a range of personal experiences including questions about MS and heredity.

By joining MyMSTeam, you gain a support group more than 150,000 members strong. The causes of MS are some of the most discussed topics.

Do other members of your family have MS? Are you worried about your children developing the disease? Do you think about your own risk factors? Share your thoughts and experiences in a comment below or on MyMSTeam. You'll be surprised to see how many others share similar stories.