The ARUP Early-Onset Alzheimer's Panel is a sequencing test that reads three genes — PSEN1, PSEN2, and APP — to find a genetic cause behind memory problems that start before age 65. It identifies a causative variant in roughly 60-80% of people who have a documented family history of early-onset Alzheimer's disease, with the test's sensitivity rising the younger a person's symptoms began, according to ARUP Laboratories' test documentation. The panel exists for a specific situation: younger adults with memory symptoms and a family pattern suggesting an inherited cause, not every person with early memory loss. Understanding what it can and cannot tell you, and what happens before and after the blood draw, matters as much as the result itself.
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
- How Accurate Is the Panel, Gene by Gene?
- Who Should Actually Be Tested?
- What Happens Before You're Tested
- What Comes After a Result
- A Related Test for Treatment Decisions
- Frequently Asked Questions
How Accurate Is the Panel, Gene by Gene?
The three genes on the panel do not contribute equally to familial early-onset Alzheimer's disease. Within the roughly 60-80% of cases where the panel finds an answer, ARUP's documentation attributes causal variants at approximately 20-70% to PSEN1, 10-15% to APP, and about 5% to PSEN2, according to ARUP's sample report for the Early-Onset Alzheimer's Panel. That leaves 20-40% of familial early-onset cases unexplained by any of the three genes. The age a person's symptoms began lines up with which gene is more likely responsible.
PSEN1 and APP variant carriers typically develop symptoms in their 30s or 40s, while PSEN2-related disease usually starts later, in a person's 50s or 60s, and shows reduced penetrance — meaning not everyone who carries a PSEN2 variant will go on to develop symptoms, per the same ARUP sample report. A negative result does not close the question. The panel only sequences the coding regions and intron-exon boundaries of APP, PSEN1, and PSEN2, has not been cleared or approved by the FDA, and a negative result does not rule out a heritable form of early-onset Alzheimer's, according to ARUP's test documentation. A clean result on these three genes can simply mean the cause lies outside what the test looks at.
Who Should Actually Be Tested?
This panel is not intended as a general screening tool for anyone worried about their memory. The 2011 practice guideline from the American College of Medical Genetics and the National Society of Genetic Counselors states that testing is most appropriate for people from families with a documented history of early-onset Alzheimer's disease, and it should always come with expert genetic counseling rather than being ordered as a standalone lab test, as reported by Newswise. For people who have no symptoms themselves but know a relative was affected, the same guideline recommends adapting the counseling protocol originally developed for Huntington's disease.
That includes checking the Alzheimer Disease & Frontotemporal Dementia Mutation Database before any result is disclosed, confirming that the family's genetic pattern matches something already known to the field, per the guideline summary on Alzforum. In practice, this means a person with memory symptoms and no known family history of early-onset disease is a poor candidate for this specific panel. The test is built around families where the inheritance pattern is already suspected, not as a first step in evaluating undiagnosed memory loss.
What Happens Before You're Tested
Genetic counseling is not an optional add-on to this test — it's built into how it's meant to be ordered. ARUP's own consent materials specify that participation is voluntary, that an ordering provider or genetic counselor should give in-person pretest and posttest counseling, and that a person being tested while still without symptoms should bring a support person who is not themselves at risk for early-onset Alzheimer's, according to ARUP's testing documentation. Counseling protocols modeled on Columbia University's Alzheimer Disease Research Center cover several things before a sample is drawn: reviewing who makes up the person's support system, explaining exactly what the test can and cannot determine, and discussing alternatives — including declining testing altogether or banking a DNA sample for relatives to use later without testing the person now, per Alzforum's summary of the counseling protocol.
- Confirm a documented family history of early-onset Alzheimer's exists before pursuing the panel
- Expect an in-person pretest counseling session, not just a lab order
- Bring a support person who is not themselves at genetic risk
- Ask what banking a DNA sample would mean as an alternative to testing now
What Comes After a Result
The next steps differ sharply depending on whether the result is positive or negative. A positive result can prompt practical decisions around career, finances, and family planning, while a negative result can relieve anxiety and inform what a person's own children might face, according to Alzforum's summary of the counseling protocol.
Results within a family don't always point the same direction, and counselors are expected to address that directly. When one sibling tests positive and another does not, the counseling protocol specifically calls for addressing survivor guilt in the sibling who tested negative, per the same Alzforum summary.
A Related Test for Treatment Decisions
Younger adults who test positive, or who are otherwise diagnosed with Alzheimer's disease and considering anti-amyloid drug treatment, face a separate but related genetic question: APOE ε4 genotyping. The FDA-reviewed label for Leqembi (an anti-amyloid treatment) states that APOE ε4 genotyping "should be performed" before starting treatment, because people with two copies of the ε4 variant — about 15% of Alzheimer's patients — face higher rates of ARIA, a brain swelling or bleeding side effect, according to coverage of the FDA label in the Pink Sheet.
This genotyping is not mandated, so a person's ε4 status can remain unknown even while pursuing treatment. But it is a distinct test from the PSEN1/PSEN2/APP panel, answering a different question: not whether Alzheimer's is inherited, but how risky a specific drug may be for the person taking it.
Frequently Asked Questions
Does a negative result on the panel mean memory problems aren't genetic?
No. The panel only covers PSEN1, PSEN2, and APP, and ARUP's documentation states a negative result does not rule out a heritable form of early-onset Alzheimer's disease.
Is APOE ε4 testing the same as the familial Alzheimer's panel?
No. APOE ε4 genotyping is a separate test tied to anti-amyloid drug safety, recommended before starting Leqembi, while the PSEN1/PSEN2/APP panel looks for an inherited cause of early-onset disease.
Can someone without symptoms be tested if a parent had early-onset Alzheimer's?
Yes, but guidelines call for adapting Huntington's disease counseling protocols, including checking a mutation database before disclosing any result.
