Clare True had autism and periodic seizures, but nothing prepared her family for Christmas Eve in 2006, when the 26-year-old went to bed after watching a movie and stopped breathing.

“I got home from a party, went to check on her just after midnight, and she was — she was gone,” said her mother, Jane True.

Paramedics tried to revive the young woman, then rushed her to the hospital, and somewhere in that firestorm of activity and grief, the Trues, Jane and her husband, Jim, considered donation. “I thought of it as a gift, her brain,” she said. “To my mind, the idea that scientists would be learning from her for years to come — how can you put a price on that?”

Clare True’s was one of 150 specimens stored in a Harvard brain bank that was ruined because of a freezer failure, doctors acknowledged this month. The loss, while a setback for scientists studying disorders like Huntington’s disease, Alzheimer’s and schizophrenia, especially mortified those working on autism, for it exposed what is emerging as the largest obstacle to progress: the shortage of high-quality autopsied brains from young people with a well-documented medical history.