Tics tend to run in families, and they certainly do in mine. However it seems there isn’t a gene that causes Tourette syndrome.
I wanted to look into this, and found a very interesting quote from my childhood neurologist when I was diagnosed.
My mum spoke about tics in the family when I was being diagnosed. This is a snippet from a letter that my neurologist sent to my GP:
I was interested to hear that Mr P—– (my dad), his father, Mr P—– senior and a half brother are all highly strung people, as is Sam. Mr P—– and his (half) brother used to have tics of a much milder kind when they were young.
Consultant Paediatric Neurologist
My dad and his half brother shared the same father, so it makes sense that they all shared similar characteristics. In this case, tics.
Sadly, the half brother (my uncle) is the only one still with us. Interestingly, he has a young son that has recently displayed tics and spoke to me for advice.
How is Tourette Syndrome passed down in families?
Over at Tourette-Action, the following is stated on their Causes of Tourette Syndrome page:
Although tics often run in families there is not a single gene that causes TS or can be tested to diagnose it. This is different to other genetic diseases such as Huntington’s disease or cystic fibrosis in which only one abnormal gene causes the disease.
Tourettes Action
So it regularly runs in families, however there isn’t a specific gene that causes it.
Inherited as a dominant gene?
I found an article that spoke a little more on genes.
It comes from cdc.gov, the Centers for Disease Control and Prevention.
Genetic studies have indicated that TS is inherited as a dominant gene, with about a 50% chance of parents passing the gene on to their children.
https://www.cdc.gov/ncbddd/tourette/riskfactors.html
So this dominant gene gives a 50% chance of passing it down to children.
This explains why tics seem so common in my family, although it seems to have affected males more than females.
Are boys affected more than girls?
In the same CDC article, it states that boys are ‘three to four times more likely than girls to display symptoms of TS.’
Again, this correlates with my family.
But this does seem to drift slightly from the ‘tic explosion‘ seen by many specialists during the pandemic.
There has been a huge increase in cases, particularly with young girls, during the lockdowns. Social media and TikTok in particular have been associated with this.
Is this triggered by watching others tic? Stress? Are a small minority of influencers even faking tics?
It is all very new, and more research is needed.
You can read my article on this sudden increase in tics here.
Do tics start at birth?
You may be aware that Tourette Syndrome symptoms vary wildly between sufferers. The same is true for when tics begin to occur.
For the majority of sufferers like myself, it starts in childhood. However for others it may appear later on in life- in teens, twenties or even later.
I will create a dedicated post on when tics begin as there is so much to talk about.
External factors
In my diagnosis, genetics were a major factor. However there could also be a reason outside of the genes.
TS is a neurodevelopmental disorder. Because it affects the neurological system and brain, external factors can cause problems.
For those that have TS, factors such as diet and stress can make symptoms worse.
An example of this can be read in this post linking my experience with caffeine to an increase in tics.
Final thoughts
Is Tourette Syndrome hereditary? Yes.
Genetics do seem to play a part in Tourette Syndrome, and external factors can also contribute.
Knowing that my family has had a history of tics helps me to understand why I have the condition.
I would recommend anyone that is looking for a diagnosis to assess whether there is a family history of tic disorders and ensure to let your GP know.
Sources:
Tourettes Action– Causes of Tourettes Syndrome
CDC– Risk factors and causes for Tourette Syndrome