People with Down Syndrome - a genetic disorder due to the presence of an extra chromosome 21 - develop Alzheimer's disease (AD) earlier (mid- to late 30s) than the general population (mid- to late 70s). To understand why, scientists have studied genes from chromosome 21 that are also involved in AD. One of those genes has already been found: It produces a protein called amyloid precursor protein (APP) that helps create protein clusters that are the hallmark of AD.
Cheryl L. Wellington and colleagues have found another gene on chromosome 21 that produces a protein that regulates the amount of cholesterol present in a cell. The scientists showed that this protein influences the distribution and processing of APP and that it is present at high levels in the brains of Down Syndrome individuals. The new discovery may provide new ways to halt AD symptoms early in these individuals.-American Society for Biochemistry and Molecular Biology
