As so many people know someone living with dementia today, it's no surprise this is one of the most common questions we're asked.
Most people know someone with dementia – more than half the people in your organisation in fact. With so many having a family member living with the condition, it’s not surprising that one of the most common questions Alzheimer’s Research UK is asked is whether dementia is genetic.
First things first, let’s establish what genes are.
Our bodies are made up of tens of thousands of genes – these dictate everything from the colour of our eyes to our likelihood of developing certain diseases.
So, can our genes cause dementia?
Dementia is caused by diseases in the brain. In most cases our likelihood of developing dementia will depend on our age, medical history and lifestyle, as well as the genes we have.
If you have a parent or grandparent with dementia, then your risk may be slightly higher than someone with no family history. However, except in rare cases, the genes we inherit from our parents may only have a small effect on our risk of developing the condition.
Are there any risk genes that increase our risk of dementia?
Thanks to investment in dementia research, our scientists have identified over 20 genes that may
slightly alter our risk of developing dementia. While having a risk gene may increase the likelihood of getting dementia, it doesn’t mean a person will definitely develop it because there are many other factors at play. Likewise, we may also have other genes that reduce our risk.
Is genetic testing available?
Alzheimer’s disease is the most common cause of dementia, and at the moment we know more about risk genes for Alzheimer’s than we do for other types of dementia. For late-onset Alzheimer’s, which is where people develop the disease from the age of 65, there is no genetic test available on the NHS. The genes discovered so far only have a relatively small effect on risk and many people who have them still won’t develop Alzheimer’s. Equally, people without these genes can still develop the disease, so such a test would not be useful.
Hear from a family impacted by an inherited form of dementia
There are some very rare forms of Alzheimer’s disease, and some cases of frontotemporal dementia, which can be caused by faulty genes and passed down in families. Having one of these rare genes makes someone almost certain to develop the disease during their lifetime – but less than 1% of dementia cases are inherited.
Those who have these forms of dementia will tend to see symptoms when they’re much younger, and this can be any time from their late 30s to 60s. If someone has an inherited form of dementia in their family, genetic testing is available on the NHS.