Familial Alzheimer’s disease (FAD) is a rare type of Alzheimer’s disease (AD) caused by a gene mutation passed down through families.
With FAD, symptoms start when you’re young. You may have symptoms in your 30s, 40s, or 50s. Most people have symptoms before age 65. Less than 5% of people with Alzheimer’s disease have FAD. Only a few hundred people have the gene that causes FAD.
FAD is also called early-onset familial Alzheimer’s disease. That’s because it may develop when you’re younger than the typical age for Alzheimer’s disease.
Familial vs. Sporadic Alzheimer's
There are two types of Alzheimer’s disease: familial and sporadic.
Familial Alzheimer’s disease, which is very rare, is caused by gene mutations that run in your family and usually develops before age 65.
Sporadic Alzheimer’s disease is more common. About 95% of people with AD have sporadic Alzheimer’s disease. Sporadic Alzheimer’s usually develops when you’re older. Doctors think it may be caused by a combination of things, including your genes and environment, but it’s still unclear.
Most cases of Alzheimer’s are sporadic. Familial Alzheimer’s disease prevalence is very low.
Familial Alzheimer's Disease Causes
Familial Alzheimer’s disease is caused by one gene mutation that’s passed down through families.
There are three genes that cause FAD:
- Presenilin 1 (PS1 or PSEN1)
- Presenilin 2 (PS2 or PSEN2)
- Amyloid precursor protein (APP)
If you have a parent with a mutation in any of these genes, you have a 50% chance of inheriting it.
FAD is caused by a mutation in one single gene. It only takes one copy of the gene mutation to cause FAD.
The most common mutation that causes FAD is PSEN1.
Familial Alzheimer's Disease Risk Factors
If you have one of the three gene mutations that cause FAD (PSEN1, PSEN2, or APP), you may develop FAD.
FAD has an autosomal dominant inheritance pattern. That means if you have a parent with one of these mutations, you have a 50% chance of developing FAD. It doesn’t skip generations.
There’s a strong family link with FAD. If one of your parents has FAD, your cousins, aunts, uncles, or grandparents who are on that parent’s side of your family may also have it. If you don’t know your biological parents or if they died young, you may not know if you have a family risk of FAD.
Other gene variants, like the apolipoprotein gene (APOE), may increase your risk. Things about your environment and lifestyle may also increase your risk.
Gender doesn’t seem to play a role. It affects men and women equally.
This is very different from the more common form of Alzheimer’s disease. If you have a family member with AD, your risk of getting AD isn’t higher. But if you have a family member with FAD, you’re much more likely to have it too. That’s because it’s caused completely by a gene mutation that’s passed down in families.
Familial Alzheimer's Disease Symptoms
Most people with FAD start having symptoms in their 30s, 40s, or 50s.
Everyone is different. You may not notice any signs at first. Or you may start to have memory problems and other Alzheimer’s disease symptoms. You may only have memory problems and no other symptoms.
At the beginning, you may have trouble remembering events or learning new information. This isn’t the same thing as regular forgetfulness that often comes with aging and happens here and there. Memory problems from AD get worse over time.
You may develop other symptoms, such as:
- Apathy or lack of interest in your usual activities, which may seem like depression
- Behavior changes
- Involuntary jerking movements, which may start in your fingers and spread to your arms and legs
- Movement issues like stiffness, unsteadiness, slowing down, or trouble walking
- Personality changes
- Seizures
- Speech deterioration
It may start with memory problems and then spread to other types of cognitive decline (a decline in mental skills). For example, you may have trouble planning or calculating things.
With FAD, it’s common for other people to notice your symptoms before you do.
If you have a parent with FAD and you inherited a gene mutation, you’ll probably start seeing symptoms around the same age they were when they first had symptoms.
If one of your parents has FAD and you’re older than they were when they started having symptoms, it may mean you didn’t inherit the gene mutation that causes FAD.
Familial Alzheimer's Disease Diagnosis
If you have signs of cognitive decline, your doctor may ask you questions about your health, your medical history, and your family health history. They may do a physical exam and run tests to see if it’s Alzheimer’s disease.
Tests for Alzheimer’s disease may include:
- Cognitive tests for memory, problem-solving, and other mental skills
- Imaging tests like CT and MRI scans that look for damage in your brain tissue
- Lab tests like blood, urine, and spinal fluid tests
Your doctor may refer you to a neurologist, neuropsychologist, or psychiatrist for more detailed testing.
Genetic testing. Your doctor may recommend familial Alzheimer’s genetic testing if you have a strong family history of Alzheimer’s disease, you’re young, and you have symptoms, or if your brain scan suggests you may have FAD.
A neurologist or other medical specialist can order a blood test to see if you have APP, PSEN1, or PSEN2, which cause FAD.
Before you do genetic testing, you’ll talk to a genetic counselor. They’ll go over what you may be concerned about and help you decide if genetic testing is right for you. They’ll also explain what the results mean and how they may impact your family.
Doctors don’t usually recommend genetic testing to predict your risk of getting Alzheimer’s.
Familial Alzheimer's Disease Treatment
There’s no treatment that will cure FAD or stop it from getting worse over time. But medications approved for treating some stages of Alzheimer’s may help ease some symptoms for a period of time.
Your doctor may recommend:
- Cholinesterase inhibitors and memantine, which may improve memory-related symptoms
- Donanemab or lecanemab, which may help slow the progression of mild Alzheimer’s
- SSRIs like citalopram and sertraline, which may help with mood changes and behavioral symptoms
- Medication for physical symptoms like jerking movements, leg stiffness, and seizures
If you’re depressed or have anxiety, your doctor may recommend medication so your symptoms don’t make your FAD worse. Psychotherapy may also help.
Researchers are trying to find out more about what causes FAD. As more studies are done, doctors hope to learn how to change the course of FAD, how to slow it down, and how to prevent it.
Familial Alzheimer's Disease Complications
As FAD gets worse, it may lead to complications.
Over time, FAD makes it harder to move, which can lead to complications like bedsores, skin infections, blood clots, and sepsis. You may fall and hurt yourself. If you have trouble swallowing, it may lead to dehydration, malnutrition, and weight loss.
In the later stages, your brain may shrink a lot. It’s possible that you won’t be able to communicate with other people. You may not recognize people’s faces, even the faces of loved ones. You may need 24-hour supervision because you can’t take care of yourself anymore.
A serious complication of Alzheimer’s is aspiration pneumonia, which is the most common cause of death from AD. This is when you can’t swallow easily and accidentally inhale pieces of food, liquids, or gastric fluids. Bacteria gets into your lungs and causes pneumonia, which may be fatal if your immune system isn’t working well.
Familial Alzheimer's Disease Prognosis
There’s no cure for FAD, and it gets worse over time.
Since FAD is rare and studies are limited, life expectancy with familial Alzheimer’s disease is unclear.
With late-onset Alzheimer’s, your life expectancy is between 8 and 12 years. But early forms of Alzheimer’s, like FAD, may be more aggressive. It may get worse faster, which may impact your life expectancy.
Living With Familial Alzheimer's Disease
Even though you can’t stop or slow down FAD, there are things you can do to improve your quality of life.
Try these tips for living with familial Alzheimer’s disease:
- Stay as mentally engaged as you can.
- Try to have a positive outlook.
- Stay active and exercise regularly.
- Eat a healthy diet.
- Limit alcohol.
- Lower stress with relaxation techniques like mindfulness and deep breathing.
- Accept help from friends and family.
- Get help from support groups and organizations like the Alzheimer’s Association and Alzheimer’s Foundation of America, which offer education and support.
Takeaways
Familial Alzheimer’s disease, or FAD, is a very rare form of Alzheimer’s disease that’s caused by one gene mutation that’s passed down in families. With FAD, you may start having symptoms when you’re young – in your 30s, 40s, or 50s. If you have a parent with FAD, you have a 50% chance of getting the mutation and developing FAD. There’s no cure, but there are things you can do to improve your quality of life with FAD.
Familial Alzheimer's FAQs
Does familial Alzheimer’s run in families?
Yes. If you have a parent with a gene mutation that causes FAD, you have a 50% chance of inheriting the gene.
Can familial Alzheimer’s skip a generation?
No. FAD has an autosomal dominant pattern of inheritance. That means you have a 50% chance of getting it if one of your parents has it. But if one of your parents died before they had symptoms, it may look like it skipped a generation.
Can you prevent familial Alzheimer’s?
Right now, there’s no known way to prevent FAD.
How old are most people when they get familial Alzheimer’s?
Most people with FAD have an early start of symptoms, before age 65. You may start noticing symptoms in your 30s, 40s, or 50s.
Can lifestyle changes help with familial Alzheimer’s?
You can’t stop or slow down the progress of FAD, but making lifestyle choices that are good for your mind and body may help you live better.
Try to:
- Eat a good diet.
- Exercise regularly.
- Limit alcohol.
- Lower stress with relaxation techniques like meditation and deep breathing.
