Is Dementia Hereditary?
It’s a common thought that crosses the minds of loved ones, the moment someone in their family is diagnosed with dementia, will I develop it too? Those who are diagnosed also fear for their children. Once you’re diagnosed, what does this mean for those who share your genetic information?
There are plenty of conditions that are influenced by genetics. In many cases, your family history will not guarantee the development of a disease or specific condition, however, your risk may increase based on environmental and lifestyle factors. Is this the case with dementia?
The answer is yes and no, as the effects of your family genes are complex and inheritance varies from case to case. Also, the cause of dementia varies, with some cases being highly influenced by genetics and others are less affected in terms of hereditary factors.
Various Causes of Dementia and Genetics
Although plenty of information is passed down, inherited from your parents, mutations aren’t the only cause for concern. The development of a disease, including conditions related to dementia, are also highly influenced based on lifestyle and environmental factors. Since dementia is not a condition itself, here are some of the most common causes and the ways in which genetics play a key role.
Alzheimer’s Disease
Being the most common cause of dementia, Alzheimer’s affects millions across the globe. In terms of genetics, Alzheimer’s is the form of dementia that is best understood at this time. There are also two types of Alzheimer’s, early and late-onset, which differ in terms of hereditary impact.
The development of early-onset tends to be directly based on genetic factors, as it’s often referred to as familial Alzheimer’s. It’s possible to pass on a genetic mutation which occurred in one of three key genes. If one of your parents had familial Alzheimer’s, you would be at a 50/50 risk of inheriting the same mutation. It’s important to note, however, that these mutations are rare and account for a small portion of Alzheimer’s cases.
In terms of late-onset, it’s believed that genetic, environmental, and lifestyle factors all play a role. It’s believed that having a relative who’s been diagnosed with late-onset Alzheimer’s increases your risk, however, it does not determine whether or not you’ll also develop this disease. This is why it’s important to follow an active, healthy lifestyle.
Being the second most common type, vascular dementia does not appear to be linked to genetics in most cases, however, researchers are still looking for risk genes. At this point, genetic factors have been linked more to the underlying causes of vascular dementia.
High cholesterol, diabetes, and hypertension are all classic examples, as these conditions can run in the family. This is why it’s crucial to follow a heart-healthy lifestyle. In extremely rare cases, vascular dementia is believed to be caused by a mutation gene, similar to that of early-onset familial Alzheimer’s.
Dementia with Lewy Bodies and Fronto-Temporal Dementia
Once again, the genetics regarding dementia with Lewy bodies is not fully understood. Like other forms of dementia, it appears that there are rare genetic cases which are directly linked to one’s family history. There are overlapping symptoms between dementia with Lewy bodies, Parkinson’s, and Alzheimer’s, so whether these conditions also share a potential genetic mutation is unclear.
Fronto-temporal dementia does often exhibit a key genetic component, as approximately one-third of all affected people have a family history regarding this form of dementia. Once again, this dementia is passed on because of a genetic mutation on a single gene.
Alzheimer’s Society. (2015). Genetics of Dementia. Retrieved from http://www.alzheimers.org.uk/site/scripts/documents_info.php?documentID=168