Zeroing in on Alzheimer’s

Hereditary Alzheimer’s disease has been shown to be the result of mutations in certain specific genes. Other cases of Alzheimer’s are also assumed to be traceable to the influence of a number of still unidentified genes. It is probable that these genes are located in a large area on chromosome 10q, which contains more than 100 genes.

Working with researchers in Gothenburg and Los Angeles, scientists at the Karolinska Institute in Stockholm, Sweden have now narrowed down the area of interest on chromosome 10 to include only three genes. The results are being published in the journal Human Mutation Online, September 24, 2003.

One of these highly interesting genes codes for the protein insulin degrading enzyme (IDE). This protein is a strong candidate for a role in Alzheimer’s owing to its biological function — it breaks down extracellular amyloid-beta protein, one of the substances that make up the senile plaque that is formed in Alzheimer’s.

The study has analyzed the DNA from 648 patients with Alzheimer’s and 663 healthy individuals. The results show a significant coupling between the limited three-gene region including the gene for IDE and the risk of disease and the severity of the disease.