To detect a rare mutation in the PSEN1 gene known to be associated with early onset familial Alzheimer disease (EOFAD)
PSEN1
PSEN1
Also Known As
PS1
Presenilin 1 Gene
S182
Formal Name
PS1 or PSEN1 Genetic Mutation Analysis
This article was last reviewed
on
This article waslast modified
on November 6, 2020.
At a Glance
Why Get Tested?
When To Get Tested?
When you are an adult who has symptoms of dementia and a strong family history of Alzheimer disease that begins before age 60 to 65 or if you are an asymptomatic adult with a family member who has early onset Alzheimer disease and an identified PSEN1 genetic mutation
Sample Required?
A blood sample drawn from a vein
Test Preparation Needed?
No test preparation is usually needed. However, prior to testing, you may wish to receive genetic counseling. This could be a helpful and important step in deciding if testing is right for you and for dealing with the result if you decide to be tested – especially if you currently have no symptoms of dementia.
Accordion Title
Common Questions
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How is it used?
PSEN1 genetic mutation analysis may be performed in adults who have a strong family history of early onset Alzheimer disease (EOFAD), especially when a specific PSEN1 mutation has been identified in other family members. It may be used to aid in the differential diagnosis of EOFAD versus other forms of early onset dementia but usually only in those with a strong family history of disease.
The PSEN1 test is not useful as a screen for the general population or for those who have late onset familial AD or sporadic AD.
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When is it ordered?
This test may be ordered when you develop symptoms associated with Alzheimer disease before 65 years of age. Signs and symptoms may include:
- Loss of memory that affects daily life—forgetting information that was recently learned. This can occur with normal aging, but the information is usually remembered later. This includes forgetting important dates or events, having to rely on memory aids, and asking for the same information again and again.
- Difficulty planning or problem solving, such as keeping track of bills and payments
- Problems completing usual tasks, such as forgetting how to get to a familiar location
- Confusion about place or time—losing track of time, forgetting where you are or how you got there
- Increasing difficulty reading or judging distances
- Problems speaking or writing—forgetting words, repeating the same thing, struggling with vocabulary
- Losing things more frequently and not being able to logically retrace steps to find them
- Impaired judgment, such as giving away unusually large amounts of money
- Increasing withdrawal from activities, including social, work or family events
- Changes in mood and personality, such as increasing anxiety, fear, suspicion and depression
PSEN1 mutation analysis may also be ordered when an asymptomatic adult has a strong family history of early onset Alzheimer disease, especially when there are multiple family members over several generations who have had or were thought to have had EOFAD.
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What does the test result mean?
If a person has a disease-causing PSEN1 mutation, it is highly likely that the person will eventually develop AD, usually at a similar age to other affected family members. The symptoms, severity, and rate of progression can vary from individual to individual. Since it is a dominant gene, each child will have a 50% chance of having the PSEN1 mutation passed on to them.
If no PSEN1 mutation is identified, it is still possible that the person has EOFAD because the specific PSEN1 mutation is not able to be identified by the existing testing method or there is a mutation in a different gene.
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Is there anything else I should know?
PSEN1 mutations are not associated with late onset sporadic AD. Some individuals will not have a strong family history because their family is not informative (i.e., key people passed away before they would have developed symptoms or their full medical histories are not known). Other issues that could confound family history are non-paternity and undisclosed adoption.
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Can this test be done at my local laboratory?
The PSEN1 test is a relatively new test that has limited use and is still rarely ordered. It is performed in only a few laboratories, so if a healthcare practitioner recommends the test, the blood sample will need to be sent to a reference laboratory.
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My father has been diagnosed with early onset Alzheimer disease. Can my doctor tell if my father has a genetic mutation without a blood test?
No, the clinical symptoms of all forms of AD are often the same. They only differ by age of onset. You cannot tell whether someone has an inherited form of AD just by looking examining them. If there is a strong family history of early onset AD, especially if another family member has had positive genetic testing, your doctor may suspect a genetic problem that may be confirmed by a blood test.
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Are there any other genetic tests that will diagnose AD?