PSEN2 genetic testing checks for a rare inherited cause of early-onset Alzheimer disease in younger adults with memory problems. It is usually ordered as sequencing of APP, PSEN1, and PSEN2 together, and coverage depends on family history and medical necessity.
PSEN2 is a deterministic early-onset Alzheimer gene. That means it follows autosomal-dominant inheritance, so a child of a carrier has a 50% chance to inherit it. Most carriers develop dementia, with typical onset from age 40 to 75.
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
- What the test checks
- Who should ask about referral
- What coverage requires
- Cost and privacy limits to know first
What the test checks
The panel confirms early-onset Alzheimer disease or tests presymptomatic relatives, according to ARUP Laboratories in its early-onset panel description. It uses massively parallel sequencing of APP, PSEN1, and PSEN2. A clinician orders it, not a direct-to-consumer kit.
A positive result points to an inherited cause. A negative result does not rule out Alzheimer disease. Most Alzheimer cases are not caused by these three genes.
Who should ask about referral
The panel is directed to symptomatic early-onset cases and at-risk relatives. ARUP Laboratories states in its testing guidance that it should not be ordered when symptoms began after age 65. Age at onset matters.
Start with genetic counseling before and after testing. When possible, test an affected relative first. Bring these details to the visit:.
- age when memory or thinking symptoms began
- three-generation history of dementia and related illness
- pattern suggesting autosomal-dominant inheritance
- known APP, PSEN1, or PSEN2 variant in the family
- reproductive plans that testing could affect
What coverage requires
One insurer policy finds testing medically necessary only with autosomal-dominant early-onset family history, a first-degree relative with a known mutation, or symptomatic early-onset disease with unknown family history for reproductive decision-making. That policy is BlueCross BlueShield of South Carolina policy CAM 287, described in the insurer medical policy. Outside those criteria, many plans call Alzheimer marker testing unproven and not covered.
Ask for prior authorization before testing. Ask for the self-pay price in writing. Get the billing code, the lab name, and whether counseling is billed separately.
Cost and privacy limits to know first
Without coverage, broad U.S. genetic test prices range from about $100 to over $2,000. Covered Medicare tests generally need a clinician order plus medical necessity, with about 20% Part B coinsurance after the deductible.
Those figures come from Medicare.org in its guide to genetic testing coverage. Federal GINA protection bars health insurers and employers from using genetic information. It does not extend to life, disability, or long-term-care insurance. Consider timing of testing if you plan to apply for those policies.
