Can Genetic Testing Determine Alzheimer’s Disease Risk?

Having a family history of Alzheimer’s disease might make you concerned about developing it yourself at an older age. In that case, you may want to undergo genetic testing to know about the probability of developing Alzheimer’s.

Multiple researchers have highlighted the link between an increased Alzheimer’s risk and a person’s genetics. Scientific findings show that individuals with first-degree relatives that have had Alzheimer’s are at a greater risk of developing the disease. The risk multiplies further if a person has more than one first-degree relative with Alzheimer’s.

Although scientific advancements, such as genetic testing, can conveniently detect hereditary diseases, the question remains, would it even be helpful to determine an individual’s risk of developing Alzheimer’s via this technique? Before we know the answer to this question, we must know about the genes and genetics of Alzheimer’s disease.

Alzheimer’s Disease and Genetics

Scientists have identified two types of genes, risk genes and deterministic genes, that are associated with late-onset and early-onset Alzheimer’s disease, respectively.

● Risk Genes

Risk genes increase the probability of Alzheimer’s development in an individual but do not guarantee the disease. These genes are associated with the most common form of dementia, the late-onset Alzheimer’s disease. Since its symptoms become apparent after the age of 65, scientists are convinced that it is not solely dependent on genetics.
Instead, other factors, including environment and lifestyle, also contribute to its development.

Researchers have discovered several risk genes. Among them, a genetic variant of the APOE (apolipoprotein E) gene on chromosome 19, APOE ε4, is the strongest indicator of an increased Alzheimer’s risk. Approximately 40-65% of people diagnosed with late-onset Alzheimer’s have this gene.

Besides APOE ε4, there are two more variants of the APOE gene viz. APOE-e2 and APOE-e3. Every individual inherits two copies of APOE genes, one from each biological parent. Inheriting a single copy of this gene increases a person’s risk. Upon inheriting two copies of this variant, the risk is augmented even further, but the disease is not guaranteed. Besides the increased risk, APOE ε4 may potentially be responsible for the onset earlier than usual.

It is important to keep in mind that not everyone with the APOE ε4 gene develops Alzheimer’s. Similarly, a person may develop it without inheriting this variant at all.

● Deterministic Genes

Deterministic genes can directly cause the disease and are responsible for early-onset familial Alzheimer’s disease. In this rare type of Alzheimer’s (which represents only 10% Alzheimer’s patients), symptoms usually appear between the 30s and mid-60s.

Any individual who inherits even one copy of these deterministic genes will develop the disorder due to their autosomal dominant pattern of inheritance. According to genetic scientists, these rare genes are found in only a few hundred extended families around the globe and account for only 1% of total Alzheimer’s cases.

Scientists have identified mutations in three genes located on different chromosomes that are responsible for causing the early-onset type:

  1. Amyloid precursor protein (APP) on chromosome 21
  2. Presenilin 1 (PSEN1) on chromosome 14
  3. Presenilin 2 (PSEN 2) on chromosome 1

These mutations are involved in the production of disease-related abnormal proteins and the degradation of the APP protein. This protein breakdown contributes to the generation of detrimental amyloid plaques, the indicator of Alzheimer’s disease.

Genetic Testing for Alzheimer’s

Although genetic testing can detect both the APOE ε4 gene and rare Alzheimer’s genes, most healthcare professionals do not recommend them for late-onset Alzheimer’s disease. This is because the presence of the APOE ε4 gene does not guarantee the development of Alzheimer’s in an individual, weakening its position as a deciding risk factor. Genetic testing for APOE ε4 is mostly done for research purposes. However, it may be appropriate for diagnosing early-onset Alzheimer’s disease.

Scientists believe that genetic testing may never predict the disease with absolute accuracy because several other factors are also involved in both its development and progression. For instance, an individual may have an increased risk of disease development even in the absence of the APOE ε4 gene due to cardiovascular diseases, environment, or other lifestyle factors.

What to Consider Before Undergoing the Test

A person knowing about their genetic risk factors may be empowering for some while being overwhelming for others. So, before you decide to get tested for Alzheimer’s risk genes or deterministic genes, you must consider the potential emotional consequences associated with the test results.

We recommend that you have a thorough conversation with your healthcare provider or physician before being tested. Furthermore, consider consulting a genetic counselor before and after deciding to take it. The genetic counselor will help you determine which test you should take based on your family history. They will also discuss the prospective emotional impact of results and brief you about the possible consequences of the test, including the effect it might have on your employment, long-term care insurance, and future plans.

Making the Home Safer

Some people with Alzheimer’s can live at home for a very long time, perhaps the rest of their lives. Others may need to be placed in assisted living, and caregivers will have to determine when that time is appropriate. It will differ for everyone.

However, taking certain precautions will help maintain a safe environment in the patient’s home.

Much of this will seem like child-proofing at the very least. It will be hard to consider and will certainly upset the patient. This is certainly dependent on what stage the person is at and how cognizant they are of their predicament.

Telephones

It is important to monitor phone calls as patients suffering from any degree of dementia and/or Alzheimer’s can be an easy target for criminals. They purchase lists of potential victims that are almost always age specific (over 65) and often utilize land lines, knowing that only seniors still use landlines with any frequency.
Even answering seemingly innocuous questions allows someone to record a “yes” or confirmation of a name that can be part of a scam.
Setting a phone to only a couple of rings so that the patient most often is
limited to outgoing calls only or simply turning off the ringer and giving the patient a mobile phone that is only to be utilized by family is another way to eliminate potential trouble.

Appliances

Lock up the ironing board, eliminate space heaters and curling irons and put a timing mechanism on the stove/oven. They really shouldn’t be cooking anything that takes more than 20 minutes so having the electrical cord of the stove go through a device that will turn off within a set amount of time can be important. Consider anything that might be a potential fire hazard.

Fireplace

Try to make fireplaces inoperable. Remove any matches, tools and firewood from the area and don’t use it even when you are there so that the habit is forgotten.

Emergency Number/Contact Information

Put a large placard near any phone that has the number for police and fire department and also the primary caregiver in addition to the home phone patient’s number and address so it is easily accessible.

Electrical Outlets

Put covers over any electrical outlets that are not in use.

Door Locks

Remove locks from any bedroom and bathroom doors so the patient cannot lock themselves in. You may want to consider door levers that are easier to operate.

Potential Weapons

Patients are prone to paranoia and fear and might hurt someone they love or even injure themselves. Remove guns, knives or anything that can be used as a weapon.

Thermostat Cover

Install a cover over the thermostat so the patient cannot accidentally turn off heat or set it too high. You can also purchase some new types of thermostats that require a password or that allow you to preset temperature parameters.

Stairs

Install two handrails for any stairs that are still being used. If a specific stair should no longer be used a door or gate will be a necessity.

Colors

Patients can sometimes relate to color better than remembering objects. A brightly colored chair might designate where you would prefer the person to sit. Similar colored rugs may guide a patient to safe paths through a house.

Alarms

Be sure smoke detectors are plentiful and operable, in addition to carbon monoxide detectors.

Spare Key

Be sure to have a spare key outside the house in case the patient accidentally locks you out or if you have to direct someone else into the home in an emergency.

Plastic Bags

A patient may accidentally smother themselves. Remove dry cleaning bags or any plastic bags if possible. Paper bags are a good option.

Computers

Eliminate or limit access to computers. They are no less dangerous than a phone for being subject to scammers.

Personal Papers

Review all paperwork. Secure anything that could be used by criminals. You might be surprised by people that have lost their homes to people that gain access to a patient’s deeds and titles.

Laundry Room

A laundry room is full of chemicals that can be dangerous.

Garage and Basement

Much like a laundry room a garage or basement can be stocked with things that can be dangerous. Keep the door to the garage locked at all times. Go a step further and hide car keys to avoid any temptation to get into the car or upset feelings when that desire is denied.

Many garages hold lawn equipment, including lawn mowers and weed eaters, which definitely should be kept off limits.

Garages sometimes have inviting work areas and lots of tools. They house sharp could-be weapons, such as shovels, axes, hoes, and rakes. Garages also store oil, paint, and other chemicals that could be deadly if ingested.

Pets

A final thing to think about are the pets in the home. Homes with pets must make adjustments to ensure safety for both the person and the pets. It is entirely possible that the person with dementia might eat cat or dog food, or mess with the litter box. For this reason, put these items in out-of-the-way places, such as the off-limits laundry room. You may have to install a doggy door to allow free access for dogs to their food or cats to the litter box.

Keep fish tanks out of reach. The combination of glass, water, electrical pumps, and potentially poisonous aquatic life could be harmful to a curious person with Alzheimer’s disease.

Also Read: Ways To Slow The Progression Of Alzheimer’s Disease

Ways to Slow the Progression of Alzheimer’s Disease

Alzheimer’s disease is the most common cause of dementia among older adults. Dementia is a progressive disorder of the brain characterized by a gradual loss of memory and cognitive functioning — thinking, remembering, reasoning — and behavioral abilities to such an extent that it interferes with a person’s daily life and activities. As the disease progresses, the person may lose the ability to perform the simplest daily tasks and respond to the environment.

Alzheimer’s Disease is frightening. The thought of getting this disease is alarming, especially if one has witnessed anyone suffering from Alzheimer’s dementia. Scientists have been working for decades to find an effective medical cure for this disease. But still, no single medical treatment has been found. That makes the situation even scarier, and one may wonder what they can do to prevent it. Fortunately, extensive research has led us to the point where we can slow its progression even if it has been diagnosed.

Alzheimer’s is a complex disease and we can’t control risk factors related to age or genetics. But there are certain lifestyle factors that can help slow the disease progression.

Identification and regulation of your risk factors, along with some lifestyle modifications, can be effective in maximizing your brain health. Here are some important factors that can help slow Alzheimer’s and dementia progression and help preserve your cognitive abilities for longer.

5 Ways to Slow the Progression of Alzheimer’s Disease

1. Healthy Diet

A healthy diet is one factor that can help reduce the risk of Alzheimer’s Disease and Dementia as it is connected with a healthy brain. Studies have suggested the effectiveness of the Mediterranean diet1 in reducing cognitive deterioration. Foods such as fruits, vegetables, nuts, whole grains, legumes, fish, and poultry, which are a major part of this diet, can have beneficial effects on brain health.

Saturated fats, sugar, and red meat should be limited in an effective diet. Consuming a lesser amount of red meat and more unsaturated fats can help prevent the development of cardiac diseases. This indirectly prevents the progression of Alzheimer’s Disease.

A study2 has exhibited many differences in the brains of a Mediterranean and American diet individual. Researchers have found more beta-amyloid proteins in the brains of people who consume traditional American food. Beta-amyloid proteins are protein particles that accumulate in the brains of Alzheimer’s patients.

2. Physical Exercise

There are various studies3 that suggest physical exercise may help in slowing cognitive decline. Just as exercise helps keep the body healthy, it also maintains good brain health by supplying increased blood and oxygen supply to the brain. According to a study4, an MRI scan after 6 to 12 months of exercise showed an improved connection between both the brain regions. Furthermore, cognitive scores of seniors with dementia, who exercised regularly, were found to be better compared to their counterparts with less physical activity.

Physical exercise can be effective in preventing, slowing the symptoms of early-stage Alzheimer’s. Moreover, it can help improve memory and learning in people with middle or late-stage disease. It is important to note that a moderate amount of physical activity (about three times per week) is enough to slow the progression of dementia.

3. Heart and Vascular Health

Preventing heart and vascular diseases is another effective way to slow a cognitive decline and Alzheimer’s progression. Besides a healthy diet and physical activity, you should keep your heart healthy too. It is essential that you stop smoking, control your cholesterol and blood pressure, maintain normal blood glucose levels, keep a healthy weight, and relax and avoid stress.

Research5 has suggested that good heart and vascular health is associated with a lesser risk of developing Alzheimer’s Disease and other forms of dementia in later life.

4. Social Engagement

Socialization is crucial as isolation is bad for physical and mental health. Our brains remain more active when we remain socially engaged. On the cellular level, it encourages new connections in the brain, leading to stimulation of activity. That also hints at social interaction as one of the ways to help prevent cognitive decline.

Alzheimer’s disease often develops in people who live isolated with very little interaction with others. A group of researchers performed a study for three years6 and concluded that the participants with less social interaction exhibited more cognitive decline. Another study7 has demonstrated that isolation and constant feelings of loneliness augment the risk of dementia and Alzheimer’s disease. Contrarily, living in communities and socializing can slow down the memory decline and the Alzheimer’s progression.

5. Mental Stimulation

Scientific studies have provided evidence that mental stimulation can help in slowing the progression of Alzheimer’s disease and dementia. The risk of dementia was reduced significantly8 in people who were actively engaged with leisure-time.

Mental stimulation strengthens the connections among brain cells, as well as, strengthening the brain cells. It may also slightly magnify the number of brain cells. To stimulate the mind, activities such as solving puzzles, playing board games, learning a language, or playing an instrument are great exercises. Furthermore, you can challenge your brain by improving your skills in something you already do.

Wrapping Up!

At present there is no cure or treatment for Alzheimer’s disease, preventing it is the best thing that we can do. There are certain lifestyle factors that, if modified properly, can significantly help in preventing cognitive decline.

References

  1. Hu, N., Yu, J.T., Tan, L., Wang, Y.L., Sun, L. and Tan, L., 2013. Nutrition and the risk of Alzheimer’s disease. BioMed research international, 2013. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3705810/
  2. https://www.nih.gov/news-events/nih-research-matters/mediterranean-diet-may-slow-development-alzheimers-disease
  3. Farina, N., Rusted, J. and Tabet, N., 2014. The effect of exercise interventions on cognitive outcome in Alzheimer’s disease: a systematic review. International Psychogeriatrics, 26(1), pp.9-18. https://pubmed.ncbi.nlm.nih.gov/23962667/
  4. Ahlskog, J.E., Geda, Y.E., Graff-Radford, N.R. and Petersen, R.C., 2011, September. Physical exercise as a preventive or disease-modifying treatment of dementia and brain aging. In Mayo Clinic Proceedings (Vol. 86, No. 9, pp. 876-884). Elsevier. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3258000/
  5. https://www.nia.nih.gov/news/cardiovascular-health-status-age-50-linked-dementia-risk-later-life
  6. Biddle, K.D., Uquillas, F.D.O., Jacobs, H.I., Zide, B., Kirn, D.R., Rentz, D.M., Johnson, K.A., Sperling, R.A. and Donovan, N.J., 2019. Social engagement and amyloid-β-related cognitive decline in cognitively normal older adults. The American Journal of Geriatric Psychiatry, 27(11), pp.1247-1256. https://pubmed.ncbi.nlm.nih.gov/31248770/
  7. Hsiao, Y.H., Chang, C.H. and Gean, P.W., 2018. Impact of social relationships on Alzheimer’s memory impairment: mechanistic studies. Journal of biomedical science, 25(1), pp.1-8. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5764000/
  8. Cheng, S.T., 2016. Cognitive reserve and the prevention of dementia: the role of physical and cognitive activities. Current psychiatry reports, 18(9), pp.1-12. https://pubmed.ncbi.nlm.nih.gov/27481112/