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Testing & Diagnosis

Genetic testing and APOE

Quick answer

APOE is a risk factor, not a diagnosis. Rare inherited forms of dementia are a separate question.

Author:
Illinois Dementia Guide editorial team
Medically reviewed by:
Amarish Dave, DO, Board Certified Neurologist
Published:
August 2026
Last medically reviewed:
August 2026
Geographic relevance:
Illinois, United States

Overview

Most Alzheimer's disease is not directly inherited. Genetic testing is most useful in younger-onset cases, strong family histories, or when considering disease-modifying therapy.

APOE

  • APOE4 raises risk but many carriers never develop dementia
  • Non-carriers can still develop Alzheimer's disease
  • APOE4 status affects ARIA risk with amyloid-targeting therapy

Inherited dementias

  • Rare autosomal dominant Alzheimer's genes and some FTD genes are directly inherited
  • Genetic counseling should precede testing
  • Results have implications for family members and should be discussed in advance

Medically reviewed. Last reviewed August 2026. This page is educational information, not individualized medical advice.

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