Is Alzheimer’s Disease Genetic ?

The news of Alzheimer’s disease on a senior loved one has a life-altering impact on the entire family. The psychological toll that caregiving alone takes can lead to severe health concerns for adult children, with higher levels of depression and stress a top issue.

Little is known about Alzheimer’s, so people focus on quality care delivery. It would have been better for affected families if researchers had at least discovered the cause of the disease, whether it’s genetic, a lifestyle condition, or a combination of both.

Many experts believe that genes contribute to the risk of contracting Alzheimer’s, although further studies are needed to confirm this claim. Here’s a roundup of studies and information to better understand how genes can raise the risk of Alzheimer’s among family members.

Understanding Genetic Factors

Genetics is the scientific study of genes and heredity—and how certain traits, qualities, and even diseases are passed from parents to offspring due to the changes in a DNA sequence. A gene is a segment of DNA that contains instructions for building one or more molecules that help the body function.

Currently, no one knows what causes Alzheimer’s disease. However, scientists assert that specific genetic mutations are responsible for many cases of this neurologic disorder. Unfortunately, they can’t identify which particular genes are associated with the disease.

Genes: How Do They Affect Health and Disease?

Genes are the blueprint that you get from your patents, and they dictate what your hair, skin, eye color, and other physical makeup should be. For example, if you and your husband have black hair, your future kids will likely inherit the same hair color.

However, there have been some interesting stories about genetic twists, such as this Nigerian couple giving birth to a white, blue-eyed baby. Doctors say that one possible reason for this is a unique genetic mutation.

Specific mutations can lead to not just unique physical traits but also genetic disorders that are more likely to be passed on. Since parents pass their genes onto their young ones, some diseases tend to cluster in families. Many of these cases often involve multiple genes.

Is Alzheimer’s Disease Genetic?

When it comes to the genetic risks for Alzheimer’s, scientists describe them in two factors: risk genes and deterministic genes.

Risk Genes

Risk genes increase one’s likelihood of developing Alzheimer’s, but it doesn’t guarantee that it will happen. As several genes are associated with Alzheimer’s, one with the most significant link to its risk is the APOE e4 gene, a variant of the APOE gene. The APOE gene is involved in making apolipoprotein E, a type of protein. This protein helps carry cholesterol and other fats through the bloodstream. So, what is its connection with Alzheimer’s?

The APOE gene comes in e2, e3, and e4 forms or major alleles. The e2 version is relatively rare and may provide some protection against Alzheimer’s disease. Meanwhile, e3 is the most common allele, but it’s not believed to affect Alzheimer’s risk.

The APOE e4 gene is said to influence Alzheimer’s risk. Unfortunately, the reason why it’s a high-risk factor is not well understood. Since the APOE gene helps carry cholesterol and other fats in the bloodstream, recent studies suggest that problems with the brain cells’ ability to process lipids (fats) may play a vital role in developing Alzheimer’s and related diseases.

Since experts believe that APOE e4 increases a person’s susceptibility to Alzheimer’s, inheriting this gene does not equate to developing it later. Some people with e4 alleles never get the disease, while others diagnosed with Alzheimer’s don’t have any e4 alleles.

Deterministic Genes

Researchers have identified three specific deterministic genes that contribute to Alzheimer’s disease: amyloid precursor protein (APP), presenilin-1 (PS-1), and presenilin-2 (PS-2). These genes are responsible for the buildup of excessive amounts of amyloid-beta peptide—a toxic protein that clumps together in the brain. This buildup causes nerve cell damage and death, which characterize Alzheimer’s.

Classification of Alzheimer’s Based on the Onset or Trigger Type

Alzheimer’s is classified into three depending on its onset or trigger type:

1. Early-Onset Alzheimer’s

Early-Onset Alzheimer’s is a brain disorder affecting individuals below 65 years old. Contrary to what many believe that only seniors are diagnosed with this progressive neurological condition, younger people may also have it.

Brain changes usually occur when a person reaches their late 40s or early 50s. Distinct features of this type are considered the outcome of a defect in Chromosome 14. It’s a rare condition, with an incidence rate of about 5 out of 100 people diagnosed with Alzheimer’s.

2. Late-Onset Alzheimer’s

Most Alzheimer’s cases are classified as late-onset, involving people older than 65. The precise genetic trigger hasn’t been identified, but scientists consider multiple risk factors, such as genetic, environmental, and lifestyle factors.

3. Familial Alzheimer’s Disease

Another type is Familial Alzheimer’s Disease (FAD), which is very rare and affects roughly 1 out of 100 Alzheimer's cases. Doctors diagnose a person with FAD if the specific genotypic pattern of the illness is connected to family genes, enabling them to predict the exact risk.

If one of the parents has any of the faulty genes (APP, PSEN1, or PSEN2), the children have a 50% chance of inheriting the disease. If a family member doesn’t inherit the disease-causing gene, they can’t pass it on to their children.

Genetic Testing: Should You Get Tested?

There is no reliable genetic test for the common sporadic form of Alzheimer’s disease. In most cases, genetic testing is not recommended. At best, it can only point to one’s susceptibility or risk to the disease. Nevertheless, genetic testing may be an option for families with young-onset familial Alzheimer's.

For anyone considering going through genetic testing, it’s crucial to get help from a healthcare professional or a certified genetic counselor.

• They will assist in finding out whether genetic testing is necessary based on family history.
• They will help ensure that the person understands the testing process, such as what to expect, what the results mean, etc.

The decision to participate in genetic testing is a personal choice. Before consenting to an assessment, consider the legal, psychological, social, and emotional implications of the testing process for yourself.

Can Alzheimer’s Be Treated?

Up to this time, there’s still no cure for Alzheimer’s or dementia. But, health experts have developed treatment methods to help ease some of the severe psychological and behavioral symptoms.

The treatment program usually involves a combination of medication and therapy. The US Food and Drug Administration has approved numerous medications to reduce difficult symptoms, such as Razadyne (galantamine) and Exelon (rivastigmine). Conversely, cognitive behavioral therapy (CBT) may also help people with Alzheimer’s suffering from anxiety, depression, and other psychological concerns.

The treatment plan for Alzheimer’s is personalized to one’s needs and health circumstances. Since it progresses differently in each person, working with your physician will help determine the best treatment approaches and strategies for your loved one.

Positive Lifestyle Changes Boost Quality of Life

Many researchers have deduced that there isn’t a single cause of Alzheimer’s disease and proposed that numerous factors, like genetics, environment, and lifestyle, can trigger it.

While you can’t alter some attributing factors like age, family history, and genetics, specific lifestyle transformations may help lower your risk for Alzheimer’s or other brain diseases. Whether it’s genetic or not, positive lifestyle changes benefit everyone.

Exercising regularly, maintaining a healthy diet, and cutting down on drinking and smoking can delay the disease progression and boost the quality of life.

Syed Rizvi

Syed has years of experience dealing with people, understanding their needs, and helping them find solutions to their problems.
As a Certified Senior Advisor (CSA), Certified Dementia Practitioner (CDP), Certified Montessori Dementia Care Professional (CMDCP), Syed is committed to working closely with Senior and their family knowing what is it like for individuals facing a challenging time, at times groping in dark trying to figure what is the appropriate next step or care level for their unique situation.
Syed and Senex Memory Advisors are fully committed to working closely with families in creating a personalized, step-by-step process memory care plan at zero cost.