Is Dementia Inherited? Understanding Alzheimer’s and Genetics Altogether

Jia Hui

Jia Hui is a content marketer who loves helping others and hopes to make this world a kinder place in any way she can.

Jia Hui

Jia Hui is a content marketer who loves helping others and hopes to make this world a kinder place in any way she can.

Published on

Given how prevalent dementia is, we are likely to know somebody who suffers from it, but it does not guarantee we will also have it. The probability of contracting one of these diseases is typically influenced by a tangled series of variables, including our age, medical history, lifestyle, and heredity. The majority of dementia cases, however, are not directly brought on by genes we inherited from our parents.

Is There a Family Gene for Dementia?

The majority of dementia patients, between 50% and 70% are affected by Alzheimer’s disease, becoming the most frequent cause of dementia. The possibility of developing Alzheimer’s Alzheimer’s disease at some point is increased by factors other than age, such as the family history of the condition. Without a previous history of dementia in the family, rare genetic abnormalities can also cause Alzheimer’s disease.

And yet, Early-onset Familial Alzheimer’s Disease, a rare condition of the illness, is regrettably handed down from parent to child. A parent’s child has a 50% probability of acquiring an eFAD-causing gene mutation if they do. The child will undoubtedly get Alzheimer’s disease if they carry that gene, typically when they are in their late 30s to 50s. Also, only a remarkably small percentage of people have this genetic risk of developing Alzheimer’s disease.

It is additionally unusual that genes play a direct role in the development of other types of dementia, including vascular dementia, dementia with Lewy bodies, and frontotemporal dementia, which particularly affects the frontal and temporal regions of the brain and are brought on by blood vessel problems or problems with the flow of blood to the brain cells.

Understanding How Genes Work

Our characteristics, including eye colour and height, are determined by our genes. They are generally passed on or acquired from our parents in some situations, and they can influence whether we will get an illness or not.

Every gene in our bodies is a small piece of the DNA code, which carries the instructions our cells need to use to create a particular protein. Our body’s cells typically carry thousands of genes. Also, our tissues and organs are made up of these proteins, which serve as the basic elements that make up life. Several of these proteins have particular jobs, such as sending messages across our nerve cells.

Does Alzheimer’s Disease Have a Genetic Basis?

Individuals acquire traits including hair colour, height, or the propensity to contract particular diseases thanks to genes, which are present in chromosomes. Specific genetic factors may directly pass a disease from one generation to the next, guaranteeing that the carrier of that gene would experience the condition. Some genes are a risk factor for only certain illnesses, which implies that they do not lead someone to get the disease but rather suggest whether or not they have a greater or lesser chance of being inclined to inherit it.

Those with a family background of dementia are more prone to have inherited genes that increase their chance of developing dementia. Moreover, lifestyle choices, social influences, and health issues can all affect a person’s likelihood of developing dementia. Age, cardiovascular conditions, diabetes, smoking, excessive alcohol consumption, depression, and small amounts of cognitive engagement are risk factors that can place a person at increased risk of developing dementia.

How Much of the Risk for Alzheimer’s Disease Is Genetic?

In most cases, having an Alzheimer’s patient parent or relative does not preclude you from getting the illness. According to studies, persons who have at minimum one first-degree family with the condition are more susceptible to getting it compared to those without it. 

Genetics is the most effective way to account for Alzheimer’s heredity. Risk gene and deterministic gene classes both affect a person’s likelihood of contracting a disease. Risk genes raise your likelihood of inheriting an illness, but they do not always ensure it. Anybody who acquires a deterministic gene will unavoidably suffer the disease linked with it because deterministic genes directly cause the condition, making dementia hereditary.

Familial early-onset types of dementia, which appear between the ages of 40 and 50, are caused by these genetic variants, which constitute 1% or fewer of all instances of Alzheimer’s. However, most patients are given a late-onset Alzheimer’s disease diagnosis, around 65 or later, which affects the vast majority of the population.

Genetic Causes of Dementia

Familial Alzheimer’s is an exceptionally uncommon type of Alzheimer’s that is passed on from parents to children. Every child does indeed have a 50% chance of acquiring FAD if one or both parents have a gene mutation that causes the condition. With this kind of Alzheimer’s disease, which affects a very tiny percentage of people, having the gene signifies that the person will ultimately get the condition, typically in their late 40s or early 50s.

Suspecting and Testing Familial Alzheimer’s Disease

Certain gene alterations can be found by genetic testing, and this test can determine whether a person has FAD and whether a child who has inherited the altered gene from either parent will eventually develop the condition, though it can’t predict when the symptoms may appear. Making sure that probable instances in the family have Alzheimer’s disease and not another type of dementia is crucial. Only a clinical exam can accomplish this, or if the patient is no longer living, a careful review of previous medical records.

It is quite difficult to decide whether to get tested for FAD, and the benefits and drawbacks need to be carefully weighed. The test provides a clear indication of whether a person will have a severe and progressive illness in their middle years yet fails to indicate a relative risk of developing dementia. 

Some people may find it helpful to make plans if they are aware that they carry the gene. They can plan their future and communicate their wishes to someone they can trust. But, given that there is currently no solution, a person must decide if they want to know they’re going to eventually develop dementia. It might be also necessary to be aware of the FAST stages of dementia if you happen to have an elderly loved one living or suffering from a dementia diagnosis for extra safety measures.

Dementia: Environmental or Genetic Factors?

Keeping in mind that dementia is a string of symptoms, it is frequently brought on by a genetically complex disease like Alzheimer’s. In some situations, genes may raise the chance of dementia development but do not directly cause it.

Rarely, a single-gene disorder that can be passed from parent to kid can directly cause dementia. For instance, frontotemporal dementia, which damages the frontal and temporal lobes of the brain, is most likely caused by a single gene mutation. While, according to the studies, researchers discovered little evidence indicating that environmental risk factors, such as exposure to air pollution, raise the incidence of dementia. Yet, they discovered substantial proof that an individual’s dementia risk is increased by a vitamin D deficit.

Genetics and Familial Alzheimer’s Disease (FAD)

Around one in twenty patients with Alzheimer’s disease receive their diagnosis when they are younger, typically in their 50s or early 60s. Although the exact origin of many cases of young-onset Alzheimer’s disease is unknown, complex interactions between genes and lifestyle are probably to blame.

Familial Alzheimer’s disease (FAD) or early-onset inherited Alzheimer’s frequently affects many people in a single-family in each generation, commonly in their 30s, 40s, or 50s. In very few cases, young-onset Alzheimer’s diseases are a result of defective genes handed down in families. The defective gene does not transmit over generations; it is directly conveyed from a parent carrying the condition to their child.

Genetics and Frontotemporal Dementia (FTD)

Frontotemporal dementia, generally recognized as Pick’s disease, is a more unusual kind of dementia that primarily affects those under the age of 65. Changes in behaviour, communication, and language are among the signs of FTD, which can manifest in many different ways. There are various FTD subtypes, and each has a unique underlying aetiology.

Some FTD sufferers have a family history, and in a few of these households, the disease may run in the family. Between one-third and fifty percent of those suffering from behavioural variants, FTD may have a familial history. For different kinds of FTD, it is believed that this number is substantially lower. Almost one in ten instances of FTD are assumed to be brought on by a defective gene that is handed down through families.

Genetics and Vascular Dementia

Generally, vascular dementia is brought on by decreased blood supply to the brain, which harms nerve cells. It might take place because of a stroke or damage to blood arteries deep in the brain. The great majority of vascular cases of dementia are not brought on by chromosomal anomalies.

Yet, there are risk genes that influence an individual’s likelihood of developing vascular dementia as well as stroke, cardiovascular disease, hypertension, and high cholesterol. However, a person’s risk might also be increased by their age and certain lifestyle choices, including smoking, not exercising, consuming alcohol in excess, and adhering to a poor diet.

Managing Geriatric Care for Elderly Dementia Patients

It can be difficult and emotionally taxing to care for an elderly loved one who has dementia of any kind. Most family caregivers have no idea how to deal with a parent who has dementia, much less one who refuses assistance. Engage with reputed dementia care in Singapore like Retire Genie if you’ve come to the point when you’re exhausted, short of funds, and in need of assistance.

When you and your family members decide what kind of specialized care your elderly parent will need, our professional geriatric care managers will be there to walk with you. Also, your elderly parent with dementia can age peacefully in place because of our affiliation with several networks and connections to in-home caregivers. As an alternative, include them in activities they could appreciate if you want to give them a comfortable daily existence. Click here for additional information about these activities.

Download Our App

Your elderly support services, now easily accessible anytime and anywhere in Singapore you are. You can ease your worries knowing that help is always on the way. Download our app today and try it for yourself!