What is the genetic defect in early onset familial Alzheimers Disease?
Some families show a mutation in the gene that encodes amyloid precursor protein on chromosome 21.
Other families show mutations on chromosome 14 (in the gene for presenilin 1) or chromosome 1 (in the gene for presenilin 2).
It is likely that other genes will be linked to the early-onset familial form of Alzheimers Disease.
These mutations are rare and account for less than 5% of Alzheimers Disease cases.
