BYU research in Nature: Rare gene variants double Alzheimer's risk

BYU coauthor is sole undergraduate on research publication

BYU researchers — including one undergraduate student — are part of a team that has identified gene variations that double a person’s risk of developing Alzheimer’s disease later in life.

Their research, led by Washington University School of Medicine, was published online today in top scientific journal Nature.

History major Cameron Schmutz is the sole undergraduate co-author on the research paper and joins biology professors John Kauwe and Perry Ridge, as well as BYU post-baccalaureate Maegan Leary, as BYU authors.

“I feel very lucky that I was able to participate in something that has such a large influence on the scientific community,” said Schmutz, who plans to attend medical school. “I’m grateful BYU was able to give me the opportunity to have this unique experience.”

The study used a process called whole exome sequencing to identify mutations in a gene never before linked to Alzheimer’s disease. Much of that sequencing took place on BYU’s campus, where Schmutz genotyped, tested and analyzed more than 5,000 DNA samples.

Although the newly identified gene variations occur rarely, making them difficult for researchers to identify, they represent a substantially increased Alzheimer’s risk for those who carry them.“

If you had the risky version of every Alzheimer’s gene that we discovered between 2009 and 2011, it would increase your chances for the disease by 15 percent,” said Kauwe, who has been involved in the discovery of several common genetic variants linked to both early-onset and more common late-onset forms of Alzheimer’s. “But if you have this single change in your DNA, it doubles your risk.”

As part of the new research, the investigators used a clever approach for identifying rare mutations: They focused on families with several members who had Alzheimer’s. The team sequenced genes from several individuals in 14 families; some of which had Alzheimer’s and some who did not.

Comparing DNA from affected people in a family to those in the same family without the disorder, the team eventually identified variations in a gene (PLD3) that showed up in affected family members. Researchers then studied another 11,000 people with and without the disease and found PLD3 gene variants doubled the risk for Alzheimer’s disease.“

To put it simply, we take a whole family of people where there is too much disease and find out what the diseased people share that the healthy people don’t,” Kauwe said.

Added Washington University coauthor Alison Goate: “The approach we’ve taken is just as important as the discovery that this gene is involved in Alzheimer’s. By studying gene variants within families, we were able to narrow down the number of variants that might cause disease. If we had been using unrelated individuals, we would not have had the statistical power to find these rare variants.”

Finding mutations linked to Alzheimer’s disease means it may be possible one day to identify people at risk many years before they develop symptoms. It’s hoped that in the future, patients could be monitored for early signs of Alzheimer’s and possibly get treatments to slow the disease’s progress.

Carlos Cruchaga, assistant professor of psychiatry at Washington University School of Medicine, is the lead author on the study.

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Originally Published in BYU News, Deseret News