Ask whether your age, family pattern, and symptoms fit hereditary Alzheimer disease, what a PSEN2 result would change for care and relatives, and what counseling and follow-up come with testing. PSEN2 is a gene on chromosome 1, and a harmful change in it can directly cause early-onset familial Alzheimer disease with progressive memory loss and dementia. Early-onset disease is uncommon and usually means symptoms before age 65, sometimes in the 30s to 50s. Because most memory problems in younger adults have other causes, these questions help you decide if testing is useful now.
Medical information disclaimer: This article is for general educational purposes only and does not provide medical advice, diagnosis, or treatment. Always consult a physician or other qualified health professional about symptoms, medications, tests, or treatment decisions.
Table of Contents
- Does my history fit PSEN2 testing?
- What would a result mean for my relatives?
- How likely is testing to find an answer?
- What support should come with testing?
Does my history fit PSEN2 testing?
Penn's genomic-medicine program recommends testing when symptoms start before age 60 or when at least three relatives in total have Alzheimer disease, as described in Penn's Alzheimer genetics guide. Early-onset disease accounts for roughly 5–10% of all Alzheimer cases, according to a Clinical Interventions in Aging review.
Ask your doctor how your age at first symptoms compares with those cutoffs. Bring a clear family history to that visit. List parents, siblings, and children, plus aunts, uncles, and grandparents with dementia, age at first symptoms, and cause of death when known.
- Symptoms before age 60, especially with progressive memory failure
- Two or more additional relatives with Alzheimer disease or dementia
- Relatives with onset in their 40s, 50s, or early 60s across generations
What would a result mean for my relatives?
PSEN2 changes pass in an autosomal dominant pattern. Genome Medical explains that a child, sibling, or parent of a carrier has a 50% chance of carrying the same variant. Ask who in the family should hear the result, when they should hear it, and whether referral for their own counseling makes sense.
Penetrance is high but not complete. The joint guideline from the American College of Medical Genetics and the National Society of Genetic Counselors lists PSEN2 testing as clinically available, with typical onset from 40 to 75 years and penetrance around 95%, as stated in the 2011 ACMG and NSGC guideline. Ask what monitoring your relatives may need, how often, and what early signs should prompt a sooner visit.
How likely is testing to find an answer?
Testing usually checks APP, PSEN1, and PSEN2 together. The Perelman School of Medicine reports that this three-gene testing finds a hereditary cause in only about 5–13% of early-onset patients. Ask what a negative result rules out, what it leaves open, and what tests come next.
A positive PSEN2 result can still change care. The Perelman School of Medicine notes it can inform family planning, relatives' risk, monitoring intervals, and possible eligibility for targeted-therapy trials or research. Ask your neurologist which trial registries accept PSEN2 carriers, what entry rules apply, and whether your care center refers directly.
What support should come with testing?
Genetic counseling should happen before and after testing. The American College of Medical Genetics and National Society of Genetic Counselors advise testing only with expert counseling, including pre-test and post-test sessions and a support person present.
Ask how to schedule both sessions, whom to bring, and how results will be shared. Children should not be tested, and direct-to-consumer APOE testing is not advised under that same guideline. Ask how the clinic protects privacy, what goes into the medical record, and what help is available for anxiety, work leave, driving, and care planning while you wait.
