Is Alzheimer's Genetic?

April 5, 2023

7 minutes

Personal Health

Learn more about the condition and the genetic factors that affect Alzheimer's predisposition

Does someone in your family have Alzheimer’s disease? If so, you may wonder if you can inherit the memory problem.

Researchers are still working to understand what causes Alzheimer’s, but they think genetics may have something to do with it. In other words, you can inherit genes that make you more likely to develop the condition. But you don’t necessarily have to have a family history of Alzheimer’s to develop the disease.

People with a sibling or parent with Alzheimer’s are more likely to develop the condition, however, than those who do not have an immediate family member with it.

About Alzheimer’s Disease

Alzheimer’s is a form of dementia, a general term used for conditions that affect memory and cognitive function. Dementia affects memory, thinking, behavior, and social skills and can significantly impact day-to-day functioning.

About 6.5 million Americans ages 65 and older live with Alzheimer’s disease. In fact, it’s the most common cause of dementia among older adults.

The cause of Alzheimer's disease is thought to be an abnormal build-up of proteins called amyloid plaques in and around brain cells that makes it difficult for neurons to "talk" to one another. Another type of protein that leads to Alzheimer’s disease causes “tangles” in the brain cells.

Communication between neurons in the brain is important for almost every biological function our bodies need to carry out. This includes everything from talking to sleeping to remembering where we placed the remote, or what our address is. When Alzheimer’s disease affects the brain, a person’s quality of life is directly impacted. They may start with mild memory loss. Over time, the plaques and tangles in the brain take over, making it difficult for the people we love to function as they were once able to.

Common symptoms of Alzheimer’s

Symptoms of Alzheimer’s can vary from person to person, but memory loss is common.

Alzheimer’s is a progressive condition, which means memory loss and other symptoms get worse over time. In its early stages, someone with Alzheimer's disease may have trouble remembering recent conversations or events.

Signs and symptoms of mild Alzheimer’s disease

The signs and symptoms of mild Alzheimer’s disease are often mistaken as normal effects of getting older. And not everyone with Alzheimer’s has every symptom.

The most common signs of early-stage Alzheimer’s include:

• Memory loss that makes everyday activities harder
• Poor judgment and making bad decisions
• Getting lost
• Losing track of dates
• Trouble planning
• Trouble solving problems
• Taking longer than usual to complete everyday tasks
• Forgetting recently-learned information
• Repeating questions
• Trouble paying bills and handling money
• Wandering
• Putting items in odd places
• Losing things
• Difficulty completing everyday tasks
• Mood and personality changes
• Increased aggression and/or anxiety

Most people with Alzheimer’s are diagnosed during the first stage of the disease.

Signs of moderate Alzheimer’s disease

People with moderate Alzheimer’s often require more supervision and care. The changes at this stage may be challenging for spouses and other family members to manage.

Signs and symptoms of moderate Alzheimer’s disease include:

• Increased memory loss and confusion
• Avoiding people and activities they usually enjoy
• Inability to learn new things
• Difficulty with language
• Struggling to read, write, and do math
• Difficulty organizing thoughts
• Shorter attention span
• Difficulty dealing with new situations
• Changes in sleeping patterns
• Trouble carrying out familiar tasks, such as getting dressed
• Occasional difficulty recognizing family and friends
• Delusions, hallucinations, and paranoia
• Impulsive behavior, such as using vulgar language or undressing at inappropriate places or times
• Inappropriate emotional outbursts
• Moodiness, such as agitation, anxiety and tearfulness
• Restlessness and wandering, especially in the late afternoon or evening
• Repetitive statements or movements

Signs of severe Alzheimer’s disease

Late-stage Alzheimer’s has devastating effects on the body. At this stage, people depend on others for every aspect of care. They need help combing their hair and eating, for example, and are typically unable to communicate or get out of bed.

Symptoms of late-stage Alzheimer’s often include:

• Trouble communicating
• No memory of recent events
• No awareness of surroundings
• Seizures
• General decline in health
• Difficulty swallowing
• Appetite loss, weight loss
• Moaning, groaning, or grunting
• Sleeping excessively
• Loss of bowel and bladder control

People with late-stage Alzheimer’s may lose their ability to swallow. This can allow food and liquids to get into their lungs. This condition is known as aspiration pneumonia. Aspiration pneumonia is a common cause of death for people with Alzheimer’s.

If you or someone you love is experiencing any of the symptoms of Alzheimer’s, it’s important to seek medical care as soon as possible as early treatment can help slow the progression of Alzheimer's disease.

Risk Factors for Alzheimer’s disease

Alzheimer’s disease is thought to develop as the result of multiple factors, such as a combination of environmental, lifestyle, and genetic factors.

Genetics

Genetics may play a role in the development of Alzheimer’s disease. This is especially true when genetics combine with other factors.

“ Research shows that older Latinos are about one-and-a-half times as likely as older whites to have Alzheimer’s and other dementias, while older African-Americans are about twice as likely to have the disease as older whites. The reason for these differences is not well understood, but researchers believe that higher rates of vascular disease in these groups may also put them at greater risk for developing Alzheimer’s.”

About genes

• You get your genes from your mother and father
• Genes carry the instructions cells need to do their job
• Humans have between 20,000 and 25,000 genes

Types of genes

There are two types of genes that affect whether or not a person may develop a disease: risk genes and deterministic genes.

• Risk genes increase the likelihood that you will develop a disease
• Deterministic genes directly cause disease.

Researchers have discovered several risk genes for Alzheimer’s disease, but deterministic genes are much more rare.

Anyone with a deterministic gene for Alzheimer’s, will develop the memory problem. But only a few hundred families worldwide have deterministic genes for Alzheimer’s disease. In fact, the genes account for less than 1 percent of Alzheimer’s disease patients. Deterministic genes cause early-onset dementia, in which symptoms develop when a person is in their early 40s to mid-50s rather than when they are 65 or older.

The deterministic genes that cause Alzheimer’s affect the way your body produces and processes beta-amyloid, which is the main protein in plaque. Beta-amyloid can clump together to form plaques which can build up between nerve cells in the brain. Clumps of beta-amyloids can stop the brain’s nerve cells from working right.

Past head trauma

A blow to your head may also increase your risk for Alzheimer’s. Your brain creates large amounts of beta amyloids following an injury. So be sure to protect your head from injury, especially during sports or other high-risk activities.

Mild cognitive impairment

Mild cognitive impairment is a stage between normal age-related decline in memory and more serious dementia. People with mild cognitive impairment may have a higher risk for Alzheimer’s.

Lifestyle

Eating a healthy diet, exercising regularly, controlling blood pressure, managing diabetes, maintaining a healthy cholesterol level, and quitting smoking can help reduce the risk for Alzheimer’s.

Heart health

Older adults with certain heart and circulatory problems have a higher risk for Alzheimer’s. Talk to your health provider about your risk and how to keep your heart healthy.

Sleep disorders

People who don’t get enough quality sleep can experience a buildup of amyloid plaques in their brains. If you struggle with getting enough good sleep, talk to your doctor, and try things like meditation for sleep which can help.

Lack of lifetime learning

Stimulating your brain with mental activities can improve brain health and reduce amyloid plaques. Find ways to keep your mind active as you age. Take a class or try a new hobby - anything new will help keep those neurons firing.

How to know if you have the Alzheimer’s gene

Medical tests, such as blood and saliva tests, can detect both deterministic and risk genes. Physicians use genetic testing to test patients with a strong family history of Alzheimer’s disease and to diagnose early-onset.

Researchers use this testing to identify participants who may have a higher risk for developing Alzheimer’s. Results of the genetic testing allow researchers to look for early brain changes in study participants, and use the tests to compare the benefits of various treatments for people with different Alzheimer’s genes.

Testing is most helpful if you have a family member with a genetic mutation for Alzheimer’s. In this case, testing can tell you if you have a deterministic gene and are certain to develop the disease.

Genetic testing can also tell you if you have inherited the Alzheimer’s risk gene. This result would mean you have a higher risk for this type of dementia, but may not necessarily develop Alzheimer’s.

Genetic counseling before and after testing can help you make sense of your results. You can talk with a genetic counselor about the potential effects the results could have on your life. You might talk about how a diagnosis of Alzheimer’s could affect your job and whether you should buy long-term care insurance.

How to get tested for the Alzheimer's gene

If you have a strong family history of Alzheimer’s, your doctor may be able to help you get tested for the Alzheimer’s gene. You can also use a home test. The FDA has approved at-home genetic testing through the 23andMe Personal Genome Service Genetic Health Risk (GHR) test. Simply send a saliva sample and receive your genetic background through the mail. Other companies offer similar tests.

Participating in research is another possible way to get tested for the Alzheimer’s gene, and to help other people in the process. Joining Evidation can help you contribute to some of the world’s leading research projects that may someday lead to a cure for Alzheimer’s disease and other conditions. Join Evidation today to learn more.