What to Know About Familial Alzheimer’s Disease (FAD)? - Lifestyle Diet Blog

What to Know About Familial Alzheimer’s Disease (FAD)?

 Rare and inherited, familial Alzheimer's disease typically manifests earlier than other types of the disease. It results from particular genetic variations that typically run in families.

A rare, hereditary form of Alzheimer's, familial Alzheimer's disease (FAD) usually appears before the age of 65.

FAD differs from the more prevalent sporadic form of Alzheimer's disease in that it is caused by specific gene mutations (changes) that are passed down via families.

Continue reading to discover more about FAD, including its causes, signs, diagnosis, and potential therapies.

How common is familial Alzheimer’s disease?

15% to 25% of all cases of Alzheimer's are familial, making it a rare type of illness. It is caused by inherited genetic alterations that are frequently connected to amyloid protein processing.

With symptoms typically manifesting before age 65, this disorder disproportionately impacts families with a history of early-onset dementia.

How does familial Alzheimer’s disease differ from sporadic Alzheimer’s disease?

While the symptoms of familial and sporadic Alzheimer's disease are similar, their causes, inheritance patterns, and onset ages are different:

• Cause: While there is no single reason for sporadic Alzheimer's, FAD is caused by particular gene mutations. The development of sporadic Alzheimer's disease is usually influenced by lifestyle, environment, and age.
• Inheritance: A person can get FAD by receiving just one copy of the faulty gene from a parent because the disease is inherited autosomally dominantly. This trend does not apply to sporadic Alzheimer's.
• Age of onset: While sporadic Alzheimer's normally manifests beyond age 65, FAD usually manifests symptoms before that age.

What genes cause familial Alzheimer’s disease?

FAD is known to be brought on by three particular genes:

• Presenilin 1 (PSEN1): Up to 5% of all cases of FAD are caused by this gene mutation, making it the most prevalent.
• Presenilin 2 (PSEN2): FAD can also result from PSEN2 mutations, however, this is less common.
• Amyloid precursor protein (APP): A major characteristic of Alzheimer's disease is the increased creation of amyloid-beta plaque, which is caused by mutations in this gene.

These genes impair normal brain function by accumulating tau protein tangles and amyloid plaques, which harm neurons (brain nerve cells).

These gene variations are similarly regarded by scientists as being almost 100% penetrant. This implies that the likelihood of developing FAD is high if you inherit the gene mutation that causes it.

How is familial Alzheimer’s disease inherited?

Usually, autosomal dominant inheritance is the pattern for FAD. This implies that your chance of getting the illness is greatly increased if you have a single copy of a mutant gene from one parent.

Each child has a 50% risk of receiving a mutation in the APP, PSEN1, or PSEN2 gene from a parent, which may result in FAD, frequently earlier than in normal Alzheimer's cases.

These mutations can be detected via genetic testing. However, since the results may influence your emotions and decision-making, think about consulting a genetic counselor before testing.

How likely am I to have Alzheimer’s disease if my parents had it?

You may be at higher risk of getting Alzheimer's if you have an Alzheimer's-afflicted parent. Alzheimer's is not caused by a single hereditary factor, but your risk may be influenced by specific gene variations.

You have a 50% chance of inheriting the genetic mutation causing familial Alzheimer's disease (FAD) if one of your parents has it. However, not all familial cases of Alzheimer's are brought on by FAD. Finding out if your family's history fits the FAD pattern might be aided by a genetic counselor.

Having a first-degree relative with sporadic Alzheimer's, like a parent or sibling, raises your chance of the illness by 10% to 30%, particularly if they were diagnosed early.

Do people with familial Alzheimer’s disease have different symptoms?

FAD sufferers frequently have symptoms that resemble those of late-onset Alzheimer's disease, including:

• memory loss
• confusion about place or time
• difficulty planning or solving problems
• changes in personality or mood

Though less frequent, seizures, altered gait, and spastic paraparesis—a type of leg muscular weakness—can also occur in certain individuals with familial Alzheimer's genetic alterations.

How do doctors diagnose familial Alzheimer’s disease?

Doctors use a thorough medical history to find trends of early-onset Alzheimer's in the family before diagnosing FAD. They could inquire as to when the symptoms started and if other family members experienced the same things.

They will then conduct cognitive tests and a physical examination. To identify early indicators of Alzheimer's, these tests assess memory, problem-solving skills, and other cognitive abilities. Younger people's symptoms could be a sign of FAD.

Imaging tests like MRIs and PET scans can be ordered by a physician. These scans can identify Alzheimer's disease-related brain abnormalities such as amyloid plaque accumulation and tissue shrinking (atrophy).

A doctor might suggest genetic testing to confirm the diagnosis. This entails looking for mutations in the genes APP, PSEN1, and PSEN2, which are frequently connected to FAD. Families with a history of early-onset Alzheimer's disease can confirm the diagnosis using genetic testing.

Does familial Alzheimer's disease have a specific treatment?

At this time, there is no cure for FAD or way to stop it from getting worse.

To control symptoms in patients with FAD, doctors may prescribe drugs that are authorized to treat specific stages of Alzheimer's disease.

Among the potential therapy approaches are:

• Medications: NMDA receptor antagonists like memantine (Namenda) and cholinesterase inhibitors like donepezil (Aricept) may aid in symptom management.
• Lifestyle interventions: A healthy diet, regular exercise, and mental stimulation may all assist in halting the disease's course.
• Clinical trials: Families with FAD might be eligible to participate in studies evaluating novel treatments, which could provide access to possible cures.

What is the outlook for people with familial Alzheimer’s disease?

Due to its hereditary basis, FAD usually advances more swiftly. Symptoms typically begin earlier, typically in the 30s to 60s, and get worse over time.

Supportive care is crucial because there is no cure, even though medicines can help control the symptoms. Depending on how quickly the disease progresses, life expectancy varies, although most people survive for eight to ten years after symptoms start.

What is the significance of FAD to Alzheimer’s research?

Research on Alzheimer's disease may benefit from FAD in several ways, including:

• Providing genetic clarity: Understanding APP, PSEN1, and PSEN2 mutations helps researchers pinpoint how the disease begins and worsens.
• Developing new therapies: Important information for creating therapies that may be effective for all forms of Alzheimer's is provided by clinical trials conducted in FAD populations.
• Advancing diagnosis and prevention: Because symptoms in affected families frequently follow predictable patterns, research on FAD aids the development of early diagnostic tools and preventative strategies.

Frequently asked questions

Is it possible to predict a person's risk of developing familial Alzheimer's disease through genetic testing?

Indeed, mutations in the APP, PSEN1, and PSEN2 genes can be found by genetic testing. You will most likely develop FAD if you have a mutation in one of these genes. Genetic counseling is necessary to assist and talk about possible consequences.

However, sporadic types of Alzheimer's cannot be reliably detected by genetic testing.

What impact does Alzheimer's illness have on family planning choices?

Preimplantation genetic testing during IVF is one option that can help lower the chance of transferring mutations linked to FAD. These choices can be guided by genetic counseling.

What support is available for families affected by familial Alzheimer’s disease?

For impacted families, support groups, internet forums, and associations such as the Alzheimer's Association offer information, consolation, and emotional support.

Takeaway

FAD is an uncommon, hereditary kind of Alzheimer's that usually strikes between the ages of 30 and 65.

Though they manifest earlier and worsen more rapidly, the symptoms of FAD are comparable to those of sporadic Alzheimer's. In addition to supporting family planning choices, genetic testing and counseling can validate the condition.

Although there is no known cure for FAD, symptoms can be managed with medication and lifestyle modifications, and access to investigational treatments may be possible through clinical trial participation.

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