Which protein is mutated in Down syndrome associated with Alzheimer's disease?

Down syndrome, also known as trisomy 21, is associated with an increased risk of developing Alzheimer’s disease later in life. This connection largely centers around the role of the beta-amyloid precursor protein (APP).

In individuals with Down syndrome, there is an extra copy of chromosome 21, which contains the gene for APP. The increased dosage of this gene leads to overproduction of the APP and subsequently beta-amyloid peptides. These peptides can aggregate to form plaques in the brain, which are characteristic of Alzheimer's disease.

The presence of these beta-amyloid plaques is one of the hallmarks of Alzheimer's pathology and contributes to neurodegeneration. Consequently, the mutation or overexpression of the protein involved in the production of beta-amyloid directly links Down syndrome with the increased prevalence of Alzheimer's disease in affected individuals.

In contrast, other options like tau protein, presenilin-1, and ApoE are also involved in Alzheimer's but are not directly related to the genetic component derived from Down syndrome. While tau protein is crucial in neurofibrillary tangle formation in Alzheimer's, it is not specifically mutated in Down syndrome. Presenilin-1 is associated with familial Alzheimer's disease and mutations in this protein lead to early-onset