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At what ages does familial early-onset Alzheimer disease usually appear?
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Alzheimer disease
Histopathologic image of neuritic plaques in the cerebral cortex in a patient with Alzheimer disease of presenile onset (onset before age 65).
Familial early-onset Alzheimer disease is a rare form of the condition that typically affects individuals during their fourth and fifth decades of life. While most cases of Alzheimer disease develop after age 60, approximately 10 percent of those who develop the disease are younger than 60 years of age. These early-onset cases are often linked to inherited genetic mutations on chromosomes 1, 14, or 21.12