Last June, John and Josephine Marr of Falmouth and their five adult children donated $2 million to launch a fund for Alzheimer’s research at Brigham & Women’s Hospital in Boston.

It was a sizable gift by any standards, but in the field of biomedical research, even a sum like $2 million only goes so far. They needed a way to keep adding to it.

So in October 2015, the Marrs recruited a large group of extended family and friends to run in the Maine Marathon. All 73 runners pledged to give the money they raised to the Alzheimer’s research fund that is named for John and Josephine Marr. They set a goal of $100,000 and exceeded it by $40,000.

For this year’s marathon on Sunday morning, the Marrs have a team of 90 runners who will participate. A goal of $150,000 could be in sight.

“It feels like there is a lot of momentum right now with Alzheimer’s research, but a lot of what is being done is done with private money,” said Abby Psyhogeos, 51, of Weston, Massachusetts, the youngest of the five Marr children. “We’re fortunate to be able to do this.”

Alzheimer’s disease, a progressive neurological disorder that affects memory, speech, balance and motor functions, has emerged as one of the defining illnesses of this generation. It’s the leading cause of death for people age 65 and older. An estimated 5 million Americans live with Alzheimer’s, including at least 37,000 in Maine.

One of them is Josephine Marr.

The 82-year-old matriarch had an ebullient, life-of-the-party personality before the disease attacked her brain. She still lives at home with her husband of 60 years, but she can no longer speak and needs sustained care.

Psyhogeos knows the current research that her family is helping fund won’t save her mother. But it could help her one day.

“Of course I think about it,” Psyhogeo said about the possibility that she, too, may develop Alzheimer’s. “I think you have to balance your life. I try to live a healthy lifestyle, but there is only so much control you have.”

MONEY PUT TO USE AT ONCE

The beneficiary of the Marrs’ generous initial donation and subsequent fundraising efforts has been the Ann Romney Center for Neurological Diseases at Brigham & Women’s Hospital in Boston.

Dr. Dennis Selkoe is the center’s co-director and a renowned researcher in the field. He has been studying Alzheimer’s since the 1980s and was among the first to draw a link between the disease and a build up of amyloid protein in the brain.

Selkoe and his team have spent approximately $850,000 from the Marr fund so far. A big chunk of that went to purchase a special instrument – one of only two in the world and the first in the U.S. – that analyzes amyloid cells in blood. Without the instrument, Selkoe and his team would be forced to study only spinal fluid, which requires a painful spinal tap.

The fund also has allowed 21 individuals to participate in a clinical trial that allows researchers to study their brain with PET imaging. The researchers hope to increase that number to 50 by the end of this year, by lowering the minimum age to participate from 50 to 65.

“To be frank, this work doesn’t get done without philanthropists like the Marrs,” Selkoe said in a phone interview Friday. “I’ve never been this excited and hopeful about Alzheimer’s research.”

One of the big benefits of the Marr fund, Selkoe said, is that researchers have been able to use it right away. Grant funding often takes a long time to come through.

“And grants don’t let us do cutting-edge work,” he said.

For instance, PET scans for patients under the age of 65 who are asymptomatic likely would not be funded with public dollars.

Much of the Alzheimer’s research has been focused on treating the disease, not preventing it, but that changed in 2013 with the creation of the A4 study, which stands for Anti-Amyloid Treatment in Asymptomatic Alzheimer’s.

The study and subsequent clinical trials involving a drug designed to break up the protein have expanded to more than 60 hospitals across North America, but the project started at Brigham & Women’s.

Selkoe’s colleague, Dr. Reisa Sperling, who directs the hospital’s Center for Alzheimer Research and Treatment, has led the A4 study and also directs the trials through the Marr fund.

Their goal is to isolate patients who have amyloid buildup consistent with the disease and then treat them with a drug that would halt its progression.

John Marr said his only caveat when he decided to collaborate with his children on the initial $2 million donation last year was that the money be put to use immediately.

“I couldn’t be happier with what they are doing,” he said of Selkoe, Sperling and their team.

YOUNGER GENERATIONS INVESTED

Psyhogeos said it’s hard to visit her mother, who is so different now from the mother she knew. Her own children, who are 12 and 13, only know their grandmother as she is now.

Still, Psyhogeos said she’s moved that her children and their many cousins have invested in the cause as well. She shared a letter that her 13-year-old daughter, Mary, sent to people asking them to sponsor her during the race.

“You may remember that my grandmother, Josephine Marr, was diagnosed with Alzheimer’s more than 10 years ago,” she wrote. “I was about 2 years old and I sadly do not have many memories of her before her illness.

“While a cure now will not benefit my grandmother, it will prevent this disease from affecting people in my parents’ and my generation. Because Alzheimer’s is a genetic illness, many members of my family are at risk for it and a future cure or treatment would hopefully prevent them from being affected.”

Mary raised more than $5,000.

John Marr, who is 84, spends most days with his wife at their home. It wasn’t how he imagined his retirement, but he’s grateful that she has been able to live at home. Nurses help out most of the day but they leave after dinner.

Sometimes the couple sit out on their screened porch overlooking a nicely manicured lawn.

On Sunday, the lawn will be filled with family and friends for a post-race barbecue.

He said it’s too bad that his wife won’t be able to understand that everyone will be there because of her.

“She ran the show,” he said. “Any credit for this family, she deserves.”