What are the other Names for this Test? (Equivalent Terms)
- Presenilin 1 Genetics Test
- PS-1 Genetics Test
- S182 Genetics Test
What is PSEN1 Genetic Mutation Analysis? (Background Information)
- PSEN1 (Presenilin 1) gene is a building block of γ-secretase (“gamma-secretase”). This is a protein that chops up other proteins (protease). The protein, cut by γ-secretase, is rendered less sticky and less prone to aggregation
- A faulty γ-secretase leads to the accumulation of the sticky, aggregatable protein, called ß amyloid (Aß), in nervous tissues. Aßs clump together into harmful plaques, which causes inflammation and deprive the neurons of nutrient-rich blood (ischemia). This results in damage to nervous tissue and can lead to Alzheimer’s disease (AD)
- There are several types of AD and these ranges in severity and underlying mechanism. Type 3 AD (AD3), or early-onset familial Alzheimer’s disease (EOFAD), is described above. EOFAD is the rarest form of AD; however, it is quick to develop and severe in its symptoms
- The PSEN1 Genetic Mutation Analysis is a genetic test that uses a blood sample, to examine the DNA sequence of PSEN1 gene for defects. It is used to diagnose EOFAD, if the disorder is suspected. It is also used to determine one’s predisposition for EOFAD
What are the Clinical Indications for performing the PSEN1 Genetic Mutation Analysis?
Clinical indicators for performing the PSEN1 Genetic Mutation Analysis include:
- Mental decline, severe enough to impair daily activity (dementia), with symptoms that may include:
- Memory loss
- Slow reaction time
- Impaired verbal and nonverbal communication
- Unexplained periodic confusion
- Alzheimer’s disease in family history
- Presence of PSEN1 gene mutation in family history
How is the Specimen Collected for PSEN1 Genetic Mutation Analysis?
Sample required: Blood
Process: Insertion of a needle into an arm vein.
Preparation required: None
What is the Significance of the PSEN1 Genetic Mutation Analysis Result?
The presence of a PSEN1 gene mutation is likely to lead to early-onset familial Alzheimer’s disease.
The laboratory test results are NOT to be interpreted as results of a "stand-alone" test. The test results have to be interpreted after correlating with suitable clinical findings and additional supplemental tests/information. Your healthcare providers will explain the meaning of your tests results, based on the overall clinical scenario.
Additional and Relevant Useful Information:
- Down syndrome results from an extra copy of the chromosome containing PSEN1. Thus, individuals with Down syndrome are at an increased risk of developing early-onset familial Alzheimer’s disease
- The presence of a certain version, ApoE4, of a protein ApoE, increases the likelihood of developing Alzheimer’s disease (AD); it hastens the onset. The reasons are poorly understood; nevertheless, ApoE testing frequently accompanies AD analyses
- A mutation in PSEN1 gene, though the most common cause of early-onset familial Alzheimer’s disease (EOFAD), is not the only cause. It is possible to test negative, yet still develop AD. Thus, caution should be exercised in such cases
- The PSEN1 Genetic Mutation Analysis is a fairly new test that is expensive and performed infrequently
Certain medications that you may be currently taking may influence the outcome of the test. Hence, it is important to inform your healthcare provider, the complete list of medications (including any herbal supplements) you are currently taking. This will help the healthcare provider interpret your test results more accurately and avoid unnecessary chances of a misdiagnosis.
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References and Information Sources used for the Article:
Campion, Dominque (1999). American Journal of Human Genetics 65 (3): 664-70. PMID 10441572
Kumar, V., Abbas, A. K., Aster, J. C., & Robbins, S. L. (2013). Robbins basic pathology (9th ed.). Philadelphia, PA: Elsevier/Saunders.
Lab Tests Online (2011, July 11). Retrieved February 28, 2014 from http://labtestsonline.org/understanding/analytes/psen1/
R J Harvey, M Skelton-Robinson, M N Rossor (2003). "The prevalence and causes of dementia in people under the age of 65 years". J Neurol Neurosurg Psychiatry 74 (9): 1206–1209. PMID 12933919