ROCHESTER, Minn. — Losing a 2-year-old child is devastating enough. But when a coping mother has to reply "I don't know" every time someone asks how it happened in the years that follow, life can become a "living hell."

That was one of the many heartbreaking stories shared by Mayo Clinic cardiologist and researcher Michael Ackerman, M.D., Sunday when he spoke on the first day of the health system's Transform 2013 conference, from which I'll also be blogging tomorrow and Wednesday.

Each year, some 100 athletes die a sudden death, he estimates, and as many as 1,000 young people suffer the same fate. Just last week, 20-year-old college track star Jenna Parlette collapsed and died during a cross country meet in Indiana. Numerous other professional and amateur athletes have died in the same fashion, from Boston Celtics center Reggie Lewis, 27, to Denver Broncos running back Damien Nash, 24. Ackerman, who heads up Mayo's sudden death laboratory, is working with others to try to understand and possibly prevent some of those cases. About one-third of the time, he estimates, the autopsy is "stone cold normal," and doctors are left with no clues.

"When it happens to young people and when it happens to athletes, it grabs us in ways that few other deaths grab us," he told attendees. "We're traumatized by deaths during war, but we expect that. That's war. We don't expect a sudden death on a football field, on a soccer field, and so we try to understand the why."

Ackerman related another story about a 17-year-old who died mysteriously, leaving behind a mother wondering: Could the same thing happen to my 13-year-old? The local coroner and newspaper were already convinced that the death had to be drug-related. But Mayo, the fifth in a line of medical institutions trying to figure out what happened, teased out a clue that the mother fell from a diving board at age 9. They tested her and found that she had long QT syndrome — "a genetic heart rhythm disorder that can cause fast, chaotic heartbeats," according to Mayo, which affects about 1 in 2,000 individuals and had been passed on to her children.

All sorts of challenges can prevent doctors from getting to that point of diagnosis, though, Ackerman says. It's hard enough to get insurers to cover treatments on live subjects, he says, let alone tests on someone who has already passed and is in "genetic purgatory." Tissue was improperly procured from the 17-year-old, a problem that persists across the U.S. The quality of the autopsy varies from county to county — Ackerman estimates that 35 to 50 percent of sudden deaths are associated with a "negative," or inconclusive, autopsy.

"There is no standard of care of how sudden death is evaluated in the United States, period," he says. "In one community, you might get every evaluation under the sun of the deceased and of the living relatives. In other communities, the most you might get is a sympathy card."

Ackerman closed by reading a letter from Theresa Brown, the mother of Dalton, who died suddenly at the age of 2 in 2001. Told by her coroner's office that the test for long QT syndrome was too costly, she was stuck in limbo for years, and comforted only when she found that Mayo had taken on the genetic testing and determined that he had the disease.

"The death of a child is always unbearable. When it occurs in a happy, healthy child for no apparent reason, it is even worse," Ackerman read from Brown's letter. "People are always shocked to hear that my son died and they always asked what happened to him. I would cringe every time I knew that question was coming because having to say 'I don't know, he just passed out and died' was its own living hell. I longed to be able to just say 'cancer, leukemia, a heart attack' or anything besides 'I don't know.' You have given me the greatest gift, and I would like to thank you from the bottom of my heart."