Ordinary in most ways, Joni Brennan quoted movie passages with precision, played trivia games at restaurants, and loved hanging with her three sisters.
But she also was extraordinary, family and friends say, and not just because she underwent a heart transplant at age 5. Determined to be more than just the new heart beating inside her, she faced a life of medical uncertainties with a joyful, relentless optimism.
“She was Joni who had the transplant, not Joni the transplant patient,” said her eldest sister, Diana, of Dorchester. “She really showed us that the heart transplant didn’t define her. Whenever I looked at her, I just saw my sister.”
Claire Joan Brennan, who as a baby was nicknamed Joni by her father, Paul, died Oct. 11 in Brigham & Women’s Hospital after a heart attack. She was 24 and lived in Quincy.
“She was a gift that God and the doctors gave back to us,” said her father, a Boston firefighter. He said she was a “kind and giving girl” who “didn’t care at all for materialistic things like cars or clothes.” Joni, he added, “brought hope and joy to people who didn’t even know they had it in them.”
She graduated in the spring from the University of Massachusetts Boston with a bachelor’s degree in psychology, and planned to become a social worker. Although her heart problems excluded many career paths in health care, “her goal since she was a kid was to work in a field where she could help people,” said her sister Megan, a nurse at Brigham & Women’s and a Quincy resident.
To celebrate her graduation early, Ms. Brennan and Megan traveled to Hawaii in March. During a layover in San Francisco, they decided to hunt down the house used as a location for the TV show “Full House,” a childhood favorite.
“We got lost on the train system, and we thought we were going to miss our flight,” Megan said. “I was freaking out, but Joni was just relaxed and laughing as always. Everything with her was an adventure.”
When Ms. Brennan was born in Boston, there was no indication of cardiac trouble; her mother, Claire, described her as a “happy baby who was always easy and always easygoing.”
She had a heart attack at age 2, then was diagnosed with cardiomyopathy. Medication helped, but at Christmastime in 1995, she became so feverish that her parents rushed her to the emergency room at Children’s Hospital in Boston, where her heart stopped.
Doctors resuscitated her, but decided her only hope for survival was a heart transplant, despite the many risks.
“She was a very sick girl, about as sick as you can get,” said Dr. Leslie Smoot, the pediatric cardiologist at Children’s who cared for Ms. Brennan until she transitioned to Brigham & Women’s two years ago.
Smoot said that when Ms. Brennan awoke after the operation, she communicated using sign language she had learned from an aunt. In time, she was eating and speaking normally.
“Children on average are more resilient, but Joni’s recovery was really something,” Smoot said, adding that credit was due to the faith and support of her “amazing” family.
“They’re like corks, they float,” she said, “and they just wrapped themselves around her.” Through years of often-painful procedures and ever-changing medications, Ms. Brennan remained “a quintessential optimist” and a “total trouper,” Smoot said.
She added that Ms. Brennan was “just so graceful in the way she handled any struggles.”
Ms. Brennan had “gorgeous long red hair,” Smoot said, and she appeared at Children’s Hospital one day with it cut off after donating it to a cancer patient.
“She was always doing things like that,” Smoot said. “She had the best attitude. You couldn’t help but love her.”
In 2009, the year Ms. Brennan graduated from Quincy High School, the Patriot Ledger featured her in a series that highlighted the achievements of local women.
“I like to think of myself as a normal kid,” Ms. Brennan said in a video created for the series.
The transplant “changed my life dramatically,” she said. “I look at life differently from my other friends. I’m grateful for everything. I enjoy life. I don’t let things bring me down.”
In third grade, Ms. Brennan began attending a program at the Germantown Neighborhood Center in Quincy, a branch of the South Shore YMCA. It was a big step for her mother, who had “wanted to keep her safe in a bubble,” because it was critical that Ms. Brennan avoid catching germs and taking health risks.
However, her mother said, “We’d saved her so she could live. And Joni just embraced life.”
Kathy Quigley, the center’s executive director, said Ms. Brennan was “beautiful and vibrant and healthier looking than anyone.” Over the years Ms. Brennan became integrally involved as a camper, then a volunteer baby sitter, a peer leader, and a head counselor.
“She was so positive and a terrific leader,” Quigley said. “The kids just loved her.”
When Ms. Brennan got her driver’s license, she drove to the center and insisted on taking Quigley for ride around the neighborhood. After her high school graduation, Ms. Brennan showed up in her cap and gown so that her mother, who now works at the center, could photograph her with program staff and participants.
“She was so much fun, she loved to have a good time,” said Carina Daniels, a friend from Quincy who accompanied Ms. Brennan on outings to Nantasket Beach and their favorite restaurants, including Grumpy White’s and La Paloma.
Daniels added that she “never knew anyone who loved her siblings the way Joni did.”
Ms. Brennan’s younger sister, Patricia, said she was “always looking out for me, always driving me places, and never complaining, not ever.”
“She made every situation, a good one or a bad one, so much better,” the Quincy resident said.
Ms. Brennan was the peacemaker during the sisters’ disputes, Diana said. “She was the happiest kid ever, and so loving,” she said. “If you ran out for 10 minutes, she’d make you feel so happy to be back home.”
Their mother said an October memorial service was attended by an “outpouring of people,” including many who said Ms. Brennan “always made them feel as though they were the most important person in the room.”
“I know mothers always say this, but she really was such a beautiful girl, and such a pure soul. She was a gift.”
Kathleen McKenna can be reached at email@example.com.