Is Alzheimer’s hereditary?

Among the elderly population, the word Alzheimer’s is often dreaded because its diagnosis opens the door to a whole new world and path which is mostly unpalatable. Even though Alzheimer’s disease (AD) is often seen in the elderly people, it is not a normal part of aging.

It is the most common cause of dementia and accounts for between 60 to 80% of dementia cases. AD is most commonly seen in people aged above 65 years, in cases where it is seen in people less than 65 years, it is described as ‘early onset Alzheimer’s disease’.

In the US, approximately 5.5 million people are affected, and about 24 million people worldwide are estimated to have AD. With a gradual shift of the world population towards aging, it is estimated that this number will double every 20 years until 2040.

What causes Alzheimer’s disease?

Several years of study about AD has resulted in a fairly well known pattern of the disease. Scientists report that the toxic microscopic changes begin to occur in the brain several years before the manifestation of the disease. The brain of people with AD have deposits outside the brain cells, called ‘plaques’ and inside the brain cells known as ‘neurofibrillary tangles’. These plaques make signals unable to pass between brain cells, while the tangles kill brain cells by preventing the normal transport of food and energy around the brain cell. This death of the brain cells lead to shrinking of the brain. These processes then lead to dementia and other symptoms associated with the disease.

Even though most people develop some plaques and tangles as they age, those with AD develop them far more and in a predictable pattern, beginning in the areas important for memory before spreading to other brain regions.

What are the risk factors for Alzheimer’s disease?

Even though the exact mechanisms are unclear with some speculations, some factors have been identified to either increase or decrease the risk of an individual having AD.

The factors that increase the risk include:

Cardiovascular disease



Type 2 diabetes

Obesity and

Traumatic brain injury

 Factors that have been noticed to be associated with decreased chances of AD include:


Leisure activity

Mediterranean diet and

Physical activity.

What are the stages of Alzheimer’s disease?

AD is a progressive disease, and the speed of progression varies among different individuals. The stages of progression determines the stage of the disease. The stages are: preclinical, mild, or early-stage AD; moderate Ad; and severe or late-stage AD

 What are the signs and symptoms of Alzheimer’s?

The manifestation of AD differ for individuals, however, in most cases, the earliest sign is loss of memory, especially of recent events.

Other signs of AD will depend on the stage of the disease.

In early-onset AD, signs noticed include: Memory loss, Poor judgment leading to bad decisions, Loss of spontaneity and sense of initiative, Taking longer to complete normal daily tasks, Repeating questions, Trouble handling money and paying bills, Wandering and getting lost, Losing things or misplacing them in odd places, Mood and personality changes, Increased anxiety and/or aggression.

In the moderate stage, the symptoms of the early stage continue to deteriorate leading to more symptoms. These include:  Inability to learn new things, Difficulty with language and problems with reading, writing, and working with numbers, Difficulty with thinking logically, reduced attention span, Difficulty carrying out multistep tasks, such as getting dressed, Problems recognizing familiar faces, Hallucinations, delusions, and paranoia, Impulsive actions such as undressing at inappropriate times or places or using vulgar language, Inappropriate outbursts of anger, Restlessness, agitation, anxiety, tearfulness, wandering, mostly in the late afternoon or evening.

In the late stage, the individual is totally dependent on others for activities of daily living. Other symptoms include: Inability to communicate, Weight loss, Seizures, Skin infections, Difficulty swallowing and Loss of bowel and bladder control. A common cause of death for AD is aspiration Pneumonia, where they take in food or liquid into the lungs instead of air.

Is Alzheimer’s disease hereditary?

AD is not hereditary strictly speaking. However, research shows that those who have a parent or sibling with Alzheimer’s are more likely to develop the disease than those who do not have a first-degree relative with Alzheimer’s. Those who have more than one first-degree relative with Alzheimer’s are at an even higher risk.

APOE-e4 is a gene which confers a risk factor for AD. Even though there is no guarantee a person with this gene will develop AD, about 40 to 65% of people with AD have this gene. People that inherit one copy of the gene from their mother or father have an increased risk of developing Alzheimer’s. Those who inherit two copies from their mother and father have an even higher risk, but not a certainty of developing the disease.

There is also a rare form of AD that usually starts before 65, the early-onset AD. Genes responsible for this are often hereditary and are estimated to account for 1% or less of Alzheimer’s cases. It occurs in every generation and if a parent has this gene, each child has a 50% chance of inheriting it.  It causes the familial early-onset forms in which symptoms usually develop between a person’s early 40s and mid-50s.

Treatment of Alzheimer’s disease

The treatment options of AD is very limited. A drug, Aducanumab is the only disease-modifying medication currently approved to treat Alzheimer’s. This drug is a human antibody that targets the protein beta-amyloid and helps to reduce the plaques, which play a role in the development of the disease. This drug is given by a medical personnel and people on it need to be monitored for side effects.

Other medications have been approved for use to reduce the symptoms of the disease.

If you or any loved one has been diagnosed with the disease, visit your doctor for proper follow up and make use of the numerous Alzheimer’s support groups to help you and your loved ones get through this though phase.