Investigating the Human Genome: Insights into Human Variation and Disease Susceptibility

7. Late-onset neurodegenerative diseases

Alzheimer’s disease

Alzheimer’s disease affects more than 35 million people worldwide (Grosgen, et al., 2010). Abundant evidence supports the hypothesis that amyloid beta plays a key role in this disease. This evidence derives from studies of familial Alzheimer’s disease in which mutations in specific genes, the presenilins, PSEN1 and PSEN2, lead to increased generation of the Abeta peptide from amyloid precursor protein (APP).

However, mutations in the presenilin genes have not been found in late-onset Alzheimer’s disease. It is not clear whether abnormal amyloid processing and deposition constitute primary defects in late-onset Alzheimer’s disease or whether they occur secondarily in response to other ...