Is MS hereditary?

“I know that one of the questions my parents had early on was whether MS would affect me and my brother, as my Dad’s children. They wanted to know if it was genetic, and, if so, what our chances were of having it.” Read ‘My Dad, MS and me’ – a blog written by @clo95 for Shift.ms‍

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Multiple sclerosis isn’t officially categorised as a hereditary or genetic condition. It isn’t passed directly from parent to child, and multiple sclerosis isn’t caused by a single gene. Other conditions are caused by a single gene – cystic fibrosis is one example – but MS is not.

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However, genes do play a part in multiple sclerosis – though over 200 different genes have been linked to MS.

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This means that, while multiple sclerosis isn’t hereditary, there is thought to be an increased risk of people in the same family being diagnosed with MS. Because family members share the same genes, there is a genetic element to multiple sclerosis.

“I’m wondering how many people here have family members with MS. My brother was also just diagnosed and our mother had it as well as her sister. Are we just some weird anomaly?” @Cojabri

This genetic link does provide a higher risk of a close family member also being diagnosed with MS, but it’s important to understand that this risk is still relatively low. 

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That level of risk can differ depending on the relationships involved. According to a 2018 study titled Genetics of Multiple Sclerosis, the ‘lifetime risk of MS in first-degree relatives of MS index cases’ is 3% – 4% for siblings, 2% for parents and 2% for children. That compares to a 0.1% to 0.3% risk in the general population. So, sharing genes does represent a higher risk of members of the same family developing multiple sclerosis, but that risk is not high.

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The risk is thought to be higher with identical twins. There is a lower risk of non-identical twins both developing multiple sclerosis than identical twins, but slightly higher than siblings, and children of a parent with MS.

In conclusion, there isn’t a definitive yes or no answer to the question of ‘is multiple sclerosis hereditary?’ It’s not, officially. Is MS genetic? Again, not officially, but genes can play a role in developing multiple sclerosis – though it’s only one of the likely causes, and the risk remains statistically low.

There’s still lots more to understand about multiple sclerosis and genetics, and research into the condition continues. If you’ve been diagnosed with MS, you can share your experience of living with multiple sclerosis with other MSers at Shift.ms. It’s free to join our forum, and start posting and commenting.