Study: 3 Chromosomes With Tiny Flaws Linked to Late-Onset Alzheimer's

Three chromosomes have been found to have tiny flaws in patients suffering from late-onset Alzheimer's disease, according to Dr. Shirley E. Poduslo, researcher at the Medical College of Georgia.

The flaws were found when researchers were studying DNA donated by Texas families affected by late-onset Alzheimer's disease. At that time Poduslo was director of basic research for the Department of Neurology at Texas Tech University Health Sciences Center in Lubbock. Poduslo has since established a similar DNA bank for patients and families in Georgia.

"If you live to be 65, you have a 5 percent change of developing Alzheimer's disease," said Poduslo. "If you live to be 85, you have a 50 percent chance. If you have a family history, there is an increased risk, no doubt about it. As our baby boomers age and retire, we are going to have a national crisis on our hands."

Poduslo enrolled nearly 500 patients, including 15 large, extended families in the TTU DNA bank, collecting family histories, patients' medical records and blood samples. Poduslo studied chromosome 19; APOE is a gene on the lower half of that chromosome and is a known risk factor for Alzheimer's disease.

She reported in the journal NeuroReport that she found evidence of markers "downstream" from APOE in some of the families.

"I assumed naively that all families would be linked with a mutation in one gene because Alzheimer's was one disease," said Poduslo. "That is not what we are finding. What we have found out is that we have three families with the disease linked with markers on chromosome 12. We have four families linked with markers on chromosome 19 and we have one family linked with markers on chromosome 3. What that means is yes, Alzheimer's definitely is genetic in these families and there are probably multiple causes for this disease."

"We now have to go back and identify the mutated genes," said Poduslo. "Once we identify the mutated genes, we are going to be able to start to correlate all of this. For example, chromosome 19 may affect people when they are over age 75 and they may have more problems with outbursts of anger and may have an increased number of plaques in certain areas of the brain. What I am thinking is that we are going to be able to start subdividing this disease into specific groups."

Poduslo is hopeful that this subdivision will help physicians optimize the treatment of Alzheimer's disease that will someday include gene therapy.

Other sources: Medical College of Georgia