The "remarkable" study "may establish new standards for the treatment of this degenerative disorder," write Raymond Ferri and Phillip Chance of the University of Washington in an accompanying editorial.

Francesco Odone, Lorenzo's older half-brother, calls the new findings "a vindication of everything my father has been putting all his efforts into for the last 15 or 20 years."

His father, study co-author Augusto Odone, 72, has been ill and unavailable for comment. Lorenzo's mother, Michaela Odone, died of cancer in 2000.

The Odones, neither of whom was trained as a scientist, hoped Lorenzo's Oil would save their son. Their desperate quest was the subject of the Oscar-nominated 1992 film Lorenzo's Oil, starring Nick Nolte and Susan Sarandon.

Before symptoms of adrenoleukodystrophy, or ALD, appeared, Lorenzo "was just the perfect boy," Francesco Odone says. "Gorgeous, precocious and smart."

Subsequent research found the oil, a combination of two fats extracted from olive oil and rapeseed oil, to be ineffective in boys who already have ALD symptoms. It could not reverse Lorenzo's brain damage.

Still, Lorenzo, who, at 27, has far surpassed the average life expectancy of boys with the childhood form of ALD, continues to take it. He lives with his father in Northern Virginia.

"He's doing very, very well," says Francesco Odone, a London resident who recently visited his brother and father. "There's been absolutely no regression for the last 20 years."

Goal: Newborn Screening

The new study followed 89 boys with ALD who took Lorenzo's Oil and ate a low-fat diet. At the start, all had normal MRI brain scans and no neurological symptoms. They had been screened for ALD, a genetic disease passed from mothers to sons, because they had an affected relative.

After an average follow-up of seven years, three-quarters of the boys still had normal MRIs and normal neurological examinations. Some may never have been destined to develop ALD in childhood, and all may still experience the milder, adult-onset form of the disorder when they reach their late 20s, says lead author Hugo Moser of Johns Hopkins University's Kennedy Krieger Institute.

Boys who develop the early MRI changes of childhood ALD could be treated with umbilical cord blood or bone marrow transplants, Moser says.

Moser's goal is to develop a newborn screening to catch all boys with ALD before symptoms appear, not just those with affected relatives. "I wake up at night and say, "good God, why don't you have the screening going?'"