Dementia is a broad term used to describe a decline in cognitive ability that interferes with daily life. It is a progressive condition that affects memory, thinking, and behaviour. Alzheimer’s disease is the most common form of dementia, accounting for approximately 60%–80% of all cases.
There are several risk factors that increase the likelihood of developing dementia, such as age, head injury, poor diet, lack of physical exercise, and smoking. However, many people wonder whether dementia is genetic and whether it runs in families.
What is genetics?
Genetics is the study of how traits and characteristics are passed down from one generation to the next. These traits are determined by genes, which are the basic units of heredity. Genes are made up of DNA, which contains the instructions for the development and function of our bodies.
Each of us inherits two copies of every gene, one from our mother and one from our father. These genes can either be dominant or recessive. If a gene is dominant, only one copy is needed to express the trait. If a gene is recessive, both copies are needed to express the trait.
Is dementia genetic?
The answer to this question is not straightforward. While there are some genetic risk factors for dementia, such as certain gene mutations that increase the likelihood of developing Alzheimer’s disease, most cases of dementia are not solely caused by genetics.
In fact, research has shown that only a small percentage of dementia cases are caused by single gene mutations, which are known as autosomal dominant mutations. These mutations are rare and are typically only found in families with a strong history of early-onset Alzheimer’s disease.
Most cases of dementia are caused by a combination of genetic and environmental factors. For example, having a family history of dementia may increase your risk of developing the condition, but it does not necessarily mean that you will develop it.
A study published in the journal Aging found that having a parent or sibling with Alzheimer’s disease increased the risk of developing the condition by approximately three times. However, the study also found that many people with a family history of Alzheimer’s disease never developed the condition.
Other genetic risk factors
While most cases of dementia are not solely caused by genetics, there are several genetic risk factors that may increase the likelihood of developing the condition. These include:
- APOE gene. The APOE gene is involved in the metabolism of cholesterol and other lipids. There are three common forms of this gene: APOE2, APOE3, and APOE4. The APOE4 variant has been found to increase the risk of developing Alzheimer’s disease, especially in individuals who inherit two copies of the gene.
- APP, PSEN1, and PSEN2 genes. These genes are involved in the production and processing of amyloid precursor protein, which can build up in the brain and form plaques, a hallmark of Alzheimer’s disease. Mutations in these genes can increase the risk of developing early-onset Alzheimer’s disease.
- TREM2 gene. This gene is involved in the immune response in the brain. Mutations in this gene have been found to increase the risk of developing Alzheimer’s disease, especially in individuals who inherit two copies of the mutation.
Takeaway
While there are some genetic risk factors for dementia, most cases of the condition are caused by a combination of genetic and environmental factors. Having a family history of dementia may increase your risk of developing the condition, but it does not necessarily mean that you will develop it.
If you are concerned about your risk of developing dementia, it is important to talk to your healthcare
provider. They can help you understand your risk factors and develop a plan to reduce your risk. This may include making lifestyle changes, such as improving your diet and increasing physical activity, as well as managing any medical conditions that may increase your risk of dementia, such as high blood pressure or diabetes.
It is also important to stay mentally and socially active, as these activities have been shown to help maintain cognitive function and reduce the risk of dementia. This can include reading, playing games, volunteering, and staying connected with friends and family.
There are several ongoing research studies exploring new treatments and prevention strategies for dementia. If you are interested in participating in a research study, talk to your healthcare provider or visit clinicaltrials.gov to learn more.
While there are genetic risk factors for dementia, most cases of the condition are caused by a combination of genetic and environmental factors. Having a family history of dementia may increase your risk, but it does not necessarily mean that you will develop the condition. By making lifestyle changes and managing any medical conditions, you can reduce your risk of developing dementia and maintain your cognitive function as you age.
Ellen Diamond, a psychology graduate from the University of Hertfordshire, has a keen interest in the fields of mental health, wellness, and lifestyle.
