Alzheimer disease (AD), a progressive neurodegenerative disorder, is the most common cause of dementia in the United States, affecting as many as 4 million people. Extensive research is under way to identify environmental and genetic risk factors for this complex disease. Currently, four genes are associated with an increased risk for AD: the amyloid precursor protein gene on chromosome 21, the Presenilin I gene on chromosome 14, the Presenilin II gene on chromosome 1, and the apolipoprotein E gene on chromosome 19. Expert and advanced practice gerontological nurses are faced with new challenges as a result of these gene discoveries. Gerontological nurses should assess for relevant environmental and genetic risk factors; obtain comprehensive family health histories recorded as pedigrees; integrate genetic information into diagnosis, intervention, and evaluation strategies; initiate and coordinate referrals to genetic specialists; and provide ongoing emotional and decision-making support for patients and families experiencing AD.