Variant of CDC2 gene may be potential risk marker for Alzheimer's

Nov 20 2007

A variant of the gene CDC2 could possibly be used as a risk marker for Alzheimer’s disease.

The gene variant is considerably more common among Alzheimer’s patients. This is shown in a dissertation from the Sahlgrenska Academy at Göteborg University in Sweden.

Alzheimer’s disease has several different causes. Since many patients have a close relative who also developed the disease, heredity is believed to be one of the most important factors.

“There is a previously identified Alzheimer’s gene that indicates an elevated risk of developing the disease, but we want to find more genes with a strong connection to Alzheimer’s. The earlier we can predict that a patient risks developing the disease, the better health-care providers can prevent and treat it,” says the research Annica Sjölander.

In her dissertation, Annica Sjölander studied different variants of a gene called CDC2. DNA analyses of blood samples from both patients and healthy individuals showed that one gene variant was considerably more common among patients with Alzheimer’s disease.

“This is the first discovery of a connection between this specific gene and Alzheimer’s. The findings must be confirmed in several other studies before we can be absolutely certain that it is a new Alzheimer’s gene that we have found,” explains Annica Sjölander.

In the study this gene variant was found in roughly half of all patients with Alzheimer’s, compared with 35 percent of the healthy control group.

The dissertation shows that patients with Alzheimer’s disease who were carriers of the gene variant also had higher levels of the protein tau, which is associated with the disease. In patients with the disease the mean level of tau in the spinal marrow fluid is about three times higher than the level in healthy individuals of the same age.

The gene CDC2 is responsible for one of the phases when a cell divides and is only active when cell division is in progress. Other research has shown that CDC2 in Alzheimer’s patients is turned on inside nerve cells where cell division does not normally take place.

“No one knows why the gene is activated, but it may be the result of a defect in the gene. It is also possible to speculate that the body is perhaps trying to compensate for lost nerve cells by having nerve cells divide,” says Annica Sjölander.

Alzheimer’s disease is one of our major public health disorders, with more than 100,000 people afflicted in Sweden. Pathological changes in the nerve cells of the brain cause the disease, which primarily affects the memory. The disorder often leads to premature death. Alzheimer’s entails not only immense suffering among patients and their loved ones, but also tremendous costs to society.

Title of dissertation: Alzheimer’s Disease: effect of tau-related genes on the pathology, neurochemistry and risk of disease.