BioEd Online

Can a controversial medicine called Lorenzo's oil really reduce the risk of developing a rare brain disease? After years of hope and provisional evidence, experts are publishing scans from children who started this therapy more than a decade ago. They say the positive results will quiet sceptics and prove the oil's worth.

In 1984, Augusto and Michaela Odone learned that their son, Lorenzo, suffered from a genetic disorder known as adrenoleukodystrophy, or ALD. The prognosis was frightening: children diagnosed with ALD experience neurological deterioration and typically die from the illness within a few years.

Faced with a lack of treatment options for their son, the Odones began pouring over books in the library for more information. They learned that ALD is related to an abnormal accumulation of very-long-chain fatty acids, particularly in the nervous system of the body. Although they tried to cut these fatty acids from their son's diet, his body continued producing them.

Recipe for hope

The literature convinced them that giving their son a different fatty acid, an oily liquid known as oleic acid, would inhibit the synthesis of long chains of saturated fats. It works simply by keeping enzymes busy making chains of unsaturated fats instead. The Odones later improved their formula by using a modified form of rapeseed oil, which seems to keep the enzymes even busier. Their medicine, which improved the health of their ailing son and inspired a Hollywood movie in the early 1990s, became known as 'Lorenzo's oil'.

It quickly became apparent that consuming these oils dramatically reduces levels of very long chain fatty acids in ALD sufferers. And preliminary results in 2002 showed that children on the oil were less likely to become ill. But no one had pinned down exact links between the medicine, a reduction in fatty acids and fewer problems.

That link has now been made. A study appearing this week in the Archives of Neurology shows that boys who took this oil had lower levels of very-long-chain fatty acids and a lower risk of developing neurological abnormalities.

Long-term view

The trial began in 1989, when researchers started giving Lorenzo's oil to patients that were known to have the genetic disorder but had not yet developed symptoms. The prescribed a daily dosage that provided approximately 20% of caloric intake. For ethical reasons, none of the 89 boys enrolled in the study was given a placebo.

Of the boys that were tracked, by 2002 only 24% developed irregularities that magnetic resonance imaging of the brain could pick up. An even smaller number, only 10%, developed neurological abnormalities. Although it is hard to interpret these results without a control group, researchers say they would normally expect about 50% of those diagnosed to produce symptoms.

Hugo Moser of Johns Hopkins University in Baltimore, Maryland, who led the study, says boys who did not consume the oil as regularly were at greater risk. This evidence, say the researchers, justifies the administration of Lorenzo's oil as a preventative treatment for people with this genetic disorder.

The results give tremendous hope to families dealing with ALD, says Paula Brazeal, president of the United Leukodystrophy Foundation in Sycamore, Illinois. But she cautions that one of the side-effects of Lorenzo's oil is that it can reduce patients' platelet count, making them susceptible to severe blood loss if injured.