A new study suggests that Alzheimer's disease may have a maternal link. The study, by New York University School of Medicine researchers, found people whose mothers have Alzheimer's, may be at higher risk of getting the disease than those whose father have it.

Researchers analyzed 49 cognitively normal individuals, from 50 to 80-years-old, who underwent a series of neuropsychological and clinical tests, and PET (positron emission tomography) scans of their brains. They did it by using a technique that labels glucose (the brain’s fuel) with a special chemical tracer. Sixteen people had a mother with the disease, and eight had a father with Alzheimer’s. The remaining subjects didn’t have a family history of the disease.

Participants with a maternal history of the disease had the largest reductions in glucose metabolism in several areas of the brain, including two brain regions involved with memory storage and retrieval. There weren't any reductions in brain energy metabolism in the people without a family history and in those with a father who had the disease.

“This is an intriguing finding,” said Mony de Leon, professor of Psychiatry and Director of the Center for Brain Health at NYU School of Medicine, in a news release. “It points to the need for more research to investigate the mechanisms of maternal transmission of this observed glucose metabolism deficit as well as to learn of any direct or indirect relationship to Alzheimer's disease."

Alzheimer’s affects more than five million Americans and is the most common form of senile dementia. People with an affected parent have a four-to 10-fold higher risk compared to individuals with no family history. It isn’t known why people with a family history are more susceptible to the disease.

Likewise, it isn’t known why individuals with a history of the disease on their mother’s side are at increased risk for Alzheimer’s, and this observation must be replicated in larger studies before it could be of use in the clinic to perhaps identify people who may be more vulnerable to the disease, said lead author Dr. Lisa Mosconi, research assistant professor of psychiatry at NYU School of Medicine, in a news release. She speculated that genes that are maternally inherited might alter brain metabolism.“Energy metabolism hasn’t been a major focus of research in Alzheimer’s, so we hope that this study will stimulate further discussion on brain activity and disease risk, which could also be important for planning targeted therapeutic interventions,” said Mosconi.

The study is published in the online edition of the Proceedings of the National Academy of Sciences.