Alzheimer's disease afflicts as many as 5.1 million people in the United States. Although there is no cure, experts believe that early detection may alleviate its symptoms.

By studying the genetic underpinnings of Alzheimer's disease, researchers in Boston have uncovered a new gene test that may become a crucial step toward early detection of the debilitating brain disorder. It may offer hope for gaining a foothold decades before dementia kicks in.

Genetic Risk Score For Alzheimer's Disease

In the new report, experts examined the genes of study participants who were young and healthy and searched for the presence of variants associated with Alzheimer's.

The study found that younger adults who carried many of the gene variations that have become markers of the disease possessed a smaller hippocampus — the region of the brain where memories are formed — compared to their peers.

While statistically significant, the link between gene variations and a smaller hippocampus was somehow weak. However, the association was still evident and detectable in healthy participants who were aged 18 to 35 years old.

On the other hand, when a large number of participants who were older and had no dementia underwent the same genetic query, the gene test was able to spot those with poorer memory and weaker cognitive function from those whose mental functions were still strong.

Scientists found that on average, those who had more genetic variants tended to have a smaller hippocampus and greater presence of beta-amyloid protein, which forms the plaque associated with Alzheimer's.

Furthermore, researchers found that over a three-year period, 15 of the 194 healthy study participants developed mild thinking impairment.

Among those who had mild cognitive impairment at the beginning of the study, 143 out of 332 went on to develop Alzheimer's disease.

Initial Research Only

Heather Snyder of the Alzheimer's Association says experts are beginning to piece together what genetic risk factors for Alzheimer's would mean.

Snyder says the findings are the first step toward understanding, but there are still ways to go. She adds that someday, genetic tests might predict a person's risk for Alzheimer's, but "we are not there yet."

Dr. Sam Gandy of Mount Sinai Hospital says the findings of the study does not mean that people should rush out to get tested to see if they are at risk for Alzheimer's. At this point, the gene test is only for research.

"It's potentially very useful in designing super early interventions," says Gandy. "But not clinically useful yet."

Details of the study are published in the journal Neurology.

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