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Also known as: PS1; PS-1; Presenilin 1 Gene; S182
Formal name: PS1 or PSEN1 Genetic Mutation Analysis
Related tests: APOE Genotyping; Tau/Aß42; PSEN2; Amyloid Precursor Protein (APP)

At a Glance

Why Get Tested?

To screen for a rare mutation in the PSEN1 gene known to be associated with early onset familial Alzheimer disease (EOFAD, also called Alzheimer disease type 3 or AD3)

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 60-65 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 in your arm

Test Preparation Needed?


The Test Sample

What is being tested?

This test looks for mutations in the PSEN1 gene sequence that have been associated with early onset familial Alzheimer disease (EOFAD, also called Alzheimer disease type 3 or AD3).

Although most Alzheimer disease (AD) cases start after the age of 65, about 5-10% of cases begin in people younger than 65 years of age. Much of this early onset AD is familial – it runs in family lines and is caused by a genetic mutation. So far, there have been three rare gene mutations that have been identified as being associated with AD3: PSEN1, PSEN2, and amyloid precursor protein (APP).

PSEN1 is the most common of these gene mutations and is thought to cause about 30% to 70% of the cases of AD3. Since PSEN1 is a dominant gene (autosomal dominant), it only takes one mutated copy, inherited from either the mother or father, to lead to the development of AD3.

Why PSEN1 mutations are associated with AD3 is not completely understood. It is thought that the normal role of the PSEN1 gene is to make the presenilin 1, a protein used in the development of the brain and spinal cord. Presenilin 1 also works with other enzymes to cut certain proteins into smaller pieces (amyloid beta peptide). A mutation of PSEN1 produces an abnormal presenilin 1 protein that no longer functions properly, resulting in a breakdown of this process. This breakdown lends itself to increased production of a longer, stickier configuration of the amyloid beta protein, which is toxic to the nervous system and eventually forms the characteristic amyloid plaques seen with AD.

So far, more than 150 mutations of the PSEN1 gene have been identified in a limited number of different family lines worldwide. The large number of mutations suggests that there may be additional mutations not yet known; thus, the PSEN1 test will not identify every person who has a PSEN1 mutation.

The analysis is made easier if a specific PSEN1 mutation has already been identified in a person's family line. The PSEN1 genetic mutation analysis is a relatively new test and is offered by a limited number of laboratories.

How is the sample collected for testing?

A blood sample is obtained by inserting a needle into a vein in the arm.

NOTE: If undergoing medical tests makes you or someone you care for anxious, embarrassed, or even difficult to manage, you might consider reading one or more of the following articles: Coping with Test Pain, Discomfort, and Anxiety, Tips on Blood Testing, Tips to Help Children through Their Medical Tests, and Tips to Help the Elderly through Their Medical Tests.

Another article, Follow That Sample, provides a glimpse at the collection and processing of a blood sample and throat culture.

Is any test preparation needed to ensure the quality of the sample?

No test preparation is needed.

The Test

Common Questions

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Due to a dramatic increase in the number of questions submitted to the volunteer laboratory scientists who respond to our users, we have had to limit the number of questions that can be submitted each day. Unfortunately, we have reached that limit today and are unable to accept your inquiry now. We understand that your questions are vital to your health and peace of mind, and recommend instead that you speak with your doctor or another healthcare professional. We apologize for this inconvenience.

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Article Sources

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NOTE: This article is based on research that utilizes the sources cited here as well as the collective experience of the Lab Tests Online Editorial Review Board. This article is periodically reviewed by the Editorial Board and may be updated as a result of the review. Any new sources cited will be added to the list and distinguished from the original sources used.

Sources Used in Current Review

Grandy, J. (2011 June 16). What's new in Alzheimer disease? Biomarkers and gene mutations as aids for detecting AD early. JAAPA [On-line information]. Available online at through Accessed April 2013.

Bird, T. (Revised 2012 October 18). Early-Onset Familial Alzheimer Disease. NCBI GeneReview [On-line information]. Available online at through Accessed March 2014.

Mayo Clinic Staff (2011 March 31) Early-onset Alzheimer's: When symptoms begin before age 65. Mayo Clinic [On-line information]. Available online at through Accessed March 2014.

Bird, T. (Revised 2014 January 30). Alzheimer Disease Overview. NCBI GeneReview [On-line information]. Available online at through Accessed March 2014.

Mayo Clinic Staff (2013 February 9). Alzheimer's genes: Are you at risk? Mayo Clinic through Accessed March 2014.

Anderson, H. (Updated 2014 March 3). Alzheimer Disease. Medscape Reference [On-line information]. Available online at through Accessed March 2014.

Stetka, B. (2013 April 1). Alzheimer Biomarkers in Clinical Practice. Medscape Today News [On-line information]. Available online at through Accessed March 2014.

Sources Used in Previous Reviews

Thomas, Clayton L., Editor (1997). Taber's Cyclopedic Medical Dictionary. F.A. Davis Company, Philadelphia, PA [18th Edition].

Pagana, Kathleen D. & Pagana, Timothy J. (2001). Mosby's Diagnostic and Laboratory Test Reference 5th Edition: Mosby, Inc., Saint Louis, MO.

Sloane, P. (1998, November 1). Advances in the Treatment of Alzheimer's Disease. American Family Physician by the American Academy of Family Physicians [On-line journal]. Available online at through

Eastman, P. (2002 March). Keeping Alzheimer's at Bay, Early Diagnosis Keeps Patients Functioning Longer. AARP Bulletin Online [On-line serial]. Available online at through

McConnell, S. et. al. Unraveling the Mysteries of Alzheimer's Disease: Exciting New Developments in Research. From panel sponsored by the Alzheimer's Association [On-line information]. Available online at through

Galasko, D., et. al. (1998). High Cerebrospinal Fluid Tau and Low Amyloid b42 Levels in the Clinical Diagnosis of Alzheimer Disease and Relation to Apolipoprotein E Genotype. Arch Neurol [On-line journal], vol (55) pages (937-945). Available online at through

ARF (1996-2002). Standard Medical Workup for Alzheimer's Disease. Alzheimer Research Forum [On-line information]. Available online at through

Family Caregiver Alliance. Fact Sheet: Alzheimer's Disease [On-line information]. Available online at through

Bird, T. (2001 June 22 last update). Alzheimer Overview. GeneReviews [On-line information. Note: It is necessary to register to use GeneReviews, but it is a free site, funded by the NIH]. Available online through

Gottlieb, F. and Lambert, J. G., [Updated by] (2002, January 2, last update). Alzheimer's Disease. MEDLINEplus [On-line information]. Available online at

Miller, M. (1998 February 18). 26 national Alzheimer's Disease Centers Collaborate on Study of the Utility of Genetic Testing for Alzheimer's. National Institutes of Health News Release [On-line press release]. Available online at through

NIH (2000). Progress report on Alzheimer's disease, taking the next steps. NIH Publication No. 00-4859 [On-line report]. Available online at through

UniSci (2002, April 08). New Approaches Seen For Early Alzheimer's Diagnosis. Daily University Science News [On-line Article]. Review of two studies found in Neuropsychology, Vol 16 (2). Available online at through

Eldercare (2002 February 28, last update). Is it Alzheimer's ... or Just Forgetfulness? Sponsored by Nebraska's Area Agencies on Aging [On-line information]. Available online at through

Diagnostic Education, Neurological Disorders, Alzheimer's Disease. Athena Diagnostics [On-line information]. Available online at through

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Hain, T. (2000 February 13). Alzheimer's Disease. Neurology, Northwestern University Medical School [3rd year neurology medical student curriculum material]. Available online at through

Kleiner-Fisman, G., Updated by (2002 January 2, last update). CSF Collection. MEDLINEplus [On-line information]. Available online at

(Reviewed 2008 December). PSEN1. Genetics Home Reference [On-line information]. Available online at through Accessed August 2009.

Bird, T. (Revised 2009 April 28). Early-Onset Familial Alzheimer Disease. GeneReviews [On-line information]. Available online at∂=alzheimer-early through Accessed August 2009.

Anderson, H et. al. (Updated 2009 June 18). Alzheimer Disease. emedicine [On-line information]. Available online at through Accessed August 2009.

Rogaeva, E. (2009 February 5). The Genetic Profile of Alzheimer's Disease: Updates and Considerations. Medscape Today from Geriatrics & Aging [On-line information]. Available online at through Accessed August 2009.

Mayo Clinic Staff (2008 September 17). Alzheimer's: Is it in your genes? [On-line information]. Available online at through Accessed August 2009.

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