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Which chromosomes contain genetic defects linked to early-onset familial Alzheimer disease?
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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).
Early-onset familial Alzheimer disease is linked to genetic defects located on three specific chromosomes:
- Chromosome 1
- Chromosome 14
- Chromosome 21
The majority of early-onset cases, approximately 70 to 80 percent, are associated with a genetic mutation on chromosome 14. The defect on chromosome 21, which codes for amyloid precursor protein, accounts for only 2 to 3 percent of these cases. While chromosome 19 is also associated with Alzheimer disease, it is primarily linked to the more common late-onset form of the condition rather than the early-onset familial type.1