If you have multiple sclerosis — an autoimmune disease that attacks nerves in the spinal cord and brain — you may worry about passing it on to your children. MS is not hereditary, meaning it’s not directly transmitted from parent to child or passed down in a family through generations. However, having a first-degree relative with MS does increase a person’s risk of developing the condition.
Among the general population, the odds of developing MS are about 1 in 750 to 1,000, according to the National Multiple Sclerosis Society. 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 relapsing MS,” said one member.
“I was diagnosed first — then my sister, who died from complications. Now my niece has it,” shared another.
Other MyMSTeam 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 affect just 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.”
MyMSTeam members with no family history of MS have 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.”
Read more about how MS affects life expectancy.
Which Risk Factors Might Be Causes of Multiple Sclerosis?
While the cause of MS is unknown, scientists have found that both environmental and genetic factors play a role in susceptibility. 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 the myelin sheath protecting nerves. Environmental factors for MS include:
- Viruses (such as the Epstein-Barr virus)
- Infections
- Smoking
- Obesity
- Geographical location (including the northern U.S., southern Canada, parts of Europe, southern Australia, and New Zealand)