Genetics & MS: Can It Be Inherited?

Recently, I’ve had the pleasure of talking to a number of different local multiple sclerosis support groups about multiple sclerosis (MS) and MS research.  These events generally involve me giving a small presentation, followed by (I’m pleased to report) lengthy question and answer sessions led by the interests of the audience.  Having noticed some common themes in questions asked, I thought it worthwhile to address them with our wider online audience as well.  The focus of today’s article is the genetics of MS.

If I have multiple sclerosis, will my kids also get it?

This is an excellent question and one that interests people for obvious reasons.  We probably all know that we are a reflection of our parents.  How many times have you heard that you have your mum’s eyes or your dad’s nose?  The physical parts of who we are, even down to a cellular level, are determined by our DNA.  DNA is the genetic material of the body and yours is a combination of your parents.

Each of these traits is determined by your genes, small segments of DNA that provide the blueprint for proteins.  These genes can have slight variations in their DNA sequence…this ends up being like a small change to a recipe, the overall meal is the same, but the taste is a little different.  The small differences in genes (called alleles) lead to slightly different versions of proteins and these give us the characteristics of who we are.

Sometimes, having a certain version of a gene can cause problems and disease.  Some examples of these ‘genetic diseases’ are haemophilia (a problem with blood clotting) and cystic fibrosis (a disease where mucus becomes sticky and builds up in a way that can lead to breathing difficulties and other problems).  In these cases, there is a clear link – you have a certain version of a gene, you get the disease.

As with a lot of things, the picture is not quite as simple in multiple sclerosis.  There are three important points to make:

1. Multiple sclerosis is not a direct genetic disease.  There have been no forms of genes identified that will definitely lead to the development of MS.

2. Having some forms of genes will increase the risk of developing multiple sclerosis.  Over 100 of these gene variations have been identified.  These can increase the risk to different extents, ranging from a very slight increase up to 3 times more likely.

3. The more of these risk alleles you have, the greater your overall risk.  A recent study showed that the effect of these gene variations is cumulative – you can read about that work in an interview we did with the lead researchers here.

We still don’t know exactly how these changes in genes make someone more likely to get multiple sclerosis, though many of the ones that have been identified are linked to the immune system.  This tells us that while multiple sclerosis isn’t a classic genetic disease like the ones I mentioned earlier, it does have a genetic component to it.  It is believed that it is an interaction between genes and environmental factors that are important in triggering multiple sclerosis.

In terms of the initial question, can you pass multiple sclerosis onto your children, the answer is complicated.  There is no form of a gene that you can pass down to your children that will mean that they definitely develop multiple sclerosis.  However, you may have alleles that could be inherited by your children that do increase their risk of developing multiple sclerosis.  Even in this instance, the risk remains relatively low.  In fact, in Australia, the chance of a child born to a parent who has MS also having the disease is a low as 1 to 2%.

Moving forward, continuing to improve our knowledge of the genes involved in MS, and how they interact with the environment, is a crucial step in improving our understanding of multiple sclerosis.