The cause was heart failure, his daughter, Cristina Odone, said.

Mr. Odone, an analyst for the World Bank who specialized in East African economies, and his wife, Michaela, a translator and linguist, became known internationally both for the ingenuity of the medicine they invented and for the bitter criticism they leveled at a medical establishment that they saw as hidebound and aloof.

The hit 1992 film based on their story, which starred Nick Nolte and Susan Sarandon, in turn drew criticism from medical experts for portraying scientists as unfeeling — and for suggesting that Lorenzo's Oil was a cure.

Lorenzo's Oil did not cure Lorenzo Odone, the couple's son, who died in 2008 at age 30 from a rare neurological disease known as adrenoleukodystrophy, or ALD. But the movie, directed by George Miller, a former physician, produced a wave of financing for research that has since confirmed the benefits of Lorenzo's Oil in certain cases, and has led to more promising treatments for this previously neglected fatal disease.

Mr. Odone and his wife began noticing changes in their son when he was about 4. A high-spirited and precocious boy who spoke three languages, Lorenzo had suddenly begun slurring his speech, stumbling and having temper tantrums at school.

Doctors first ascribed the symptoms to a tropical disease, possibly contracted in Comoros, off the coast of Mozambique, where Mr. Odone had taken his family while working on a project for the bank. They had recently returned to Washington, where the World Bank has its headquarters.

After two years of testing, though, doctors told the Odones that their son had ALD. Because it was so rare, affecting one in 45,000 people, there was not very much known about it, and it attracted little money for research. What the doctors did know was that it was fatal and incurable, and that Lorenzo would probably not live more than two more years.

"We were being told to go home and watch Lorenzo die," Mr. Odone wrote in an essay published in 2011. "We couldn't and didn't."

They began an improbable mad dash to find a cure. Mr. Odone began studying the biochemistry of the nervous system. He and his wife called doctors, biologists and other researchers around the world to assemble the few far-flung experts on ALD for a symposium, at which some learned of one another's work for the first time.

By the late 1980s — distilling what they had learned, as they later recalled, through doggedness, serendipity and ignorance of their own limits — the Odones, with a few scientist allies, developed a chemical compound that seemed to slow Lorenzo's disease. They called the medicine, an extract of acids in olive and rapeseed oils, Lorenzo's Oil.

The compound, which apparently worked by breaking down the long-chain fatty acids considered a major cause of damage to nerve cells in people with ALD, has been the subject of several long-term studies, one of which is still in progress. Another, completed in 2005, found that Lorenzo's Oil helped children with ALD if used before they started showing symptoms, but that it was less effective once the degenerative process had begun. The Food and Drug Administration still considers the treatment experimental.

From about the age of 8, Lorenzo was paralyzed and blind, unable to speak, dependent on a feeding tube and kept alive by round-the-clock nursing care and the nearly full-time ministrations of his parents, who talked to him constantly and insisted that visitors do likewise, though even the Odones could never be certain about his level of awareness. Despite his disabilities, his parents believed that Lorenzo recognized their voices, loved music and enjoyed being alive.

Mr. Odone conceded, mainly in interviews he gave after the death of his wife in 2000, that he had sometimes wondered if that was enough of a life to justify the extraordinary lengths to which he and his wife had gone.

"Lorenzo never regained his faculties," said Cristina Odone, one of Mr. Odone's two children from a previous marriage, in a phone interview last week. That had been the objective, after all.

"If you had ever walked into the room and seen how Lorenzo responded to the way my father and Michaela embraced him in life, wrapped him in love, you would see he was a living being who knew he was loved. That's what they gave him," she said. "But it was very difficult."

Augusto Daniel Odone was born in Rome on March 6, 1933, to Angelo and Maria Odone. His father was a general in the Italian Army and his mother was a novelist.

He grew up in Gamalero, Italy, received a law degree from the University of Rome and later studied at the University of Kansas on a Fulbright scholarship. He worked for a bank that specialized in reconstruction and development in southern Italy before joining the World Bank in 1969.

His first marriage, to Ulla Sjostrom, ended in divorce. His second wife, the former Michaela Murphy, was Lorenzo's mother. Besides his daughter, he is survived by a son, Francesco, and a granddaughter.

J. Michael Bishop, an American microbiologist who shared the 1989 Nobel Prize in Medicine, described "Lorenzo's Oil," the film, as misleading in its claims about the oil extract and "deeply troubling for its portrayal of medical scientists as insensitive, close-minded and self-serving" — a viewpoint he found to be encapsulated by one particular line spoken late in the film by Lorenzo's father: "These scientists have their own agenda, and it is different from ours."

But, writing in The Bulletin of the American Academy of Arts and Sciences in 1995, Dr. Bishop cautioned fellow scientists against dismissing the public sentiment the film conveyed. "Here is a warning science cannot take lightly," he wrote — "a warning to explain ourselves more clearly, a warning even to change some of our ways."