While research has not yet linked an early biomarker to AD, the cause of early-onset AD in people with DS (DS-AD) could indeed lie in their genes. Down Syndrome is caused by a partial or complete extra copy of chromosome 21. Chromosome 21 carries the gene for amyloid precursor protein that is implicated in increased amyloid- beta plaque deposition in the brains of people with AD or DS-AD. However, differences may exist between the two conditions. In brains of people with DS, diffuse amyloid-beta deposits appear during childhood or early adulthood, while these deposits appear at an older age in those with late-onset AD.
More on Progressnotes, MUSC’s Medical Magazine