New Genetic Clues to Alzheimer’s Cause Found

Scientists continue to look for the cause or causes of Alzheimer’s disease in genetics, lifestyle, and injuries to the head. Alzheimer’s is the most common type of dementia, and generally occurs in older patients. In persons over age 65 one in eight will develop the disease, and in those over age 85 almost half have Alzheimer’s. Alzheimer’s cannot be diagnosed with 100% accuracy except by autopsy. Autopsy has shown that the brain cells of all people who die at an advanced age have some plagues and tangles in their brains. These are deposits of proteins that accumulate in the spaces between nerve cells and inside of nerve cells. People diagnosed with Alzheimer’s prior to their deaths have far more of the plaques and tangles than others. It is not clearly understood how the plagues and tangles affect the patient but one theory is that they block nerve cells communications and thus their ability to survive.

Dozens of genes have been linked with Alzheimer’s, notably the APOE4 gene which raises the risk of developing the disease. Now researchers have identified four additional genes that significantly increase the risk of Alzheimer’s disease. Some genes, associated with the most common form of Alzheimer’s, late onset, appear linked to known genetic risks according the team at Harvard Medical School in Boston. Rudolph Tanzi of Massachusetts General Hospital, who led the study, said “We are on the cusp of a rare 'science moment’ that could alter the way that we diagnose, treat and prevent Alzheimer’s disease.”

The team studied 1,300 hundred families for the study, published in the American Journal of Human Genetics. This involved a genome-wide association study, using gene chips to check the activity of genes among families with Alzheimer’s patients compared with families whose members did not have the disease. The strongest indications were from a stretch of DNA on chromosome 14. What the new gene does is not clear, though the study says that it may control the activity of other genes. The researchers will continue to study the genetic implications that either provide greater risk or protect against the disease.

There is no cure for Alzheimer’s, current drug therapies can delay the symptoms, but patients will lose their memories, ability to move around on their own, and ability to care for themselves. It is estimated that as many as 5.2 million Americans have the disease, and the number of new cases per year will continue to rise.

The study was funded by the Cure Alzheimer’s Fund which initiated the Alzheimer’s Genome Project and contributed $3 million towards the study. Cure Alzheimer’s is a public charity established to fund targeted research on the disease. For more information, please visit www.curealzfund.org.