GAINESVILLE, Fla. - Several hundred babies are born in the United States each year with an inherited disorder known as PKU, which requires adherence to an unpleasant protein-free diet to thwart development of mental retardation.
Now University of Florida researchers report a small victory on the road to a cure: In male laboratory mice, they have effectively reversed the condition with a single treatment of gene therapy. The findings raise the hope that as the science progresses in coming years, people with the disorder will no longer have to shun so much of the typical human diet, including meat, fish, poultry, nuts and dairy products.
"Some people mistakenly believe that there already is a cure for PKU, but cure should be in quotation marks," said Philip J. Laipis, who is presenting his research Saturday (6/2) at the American Society of Gene Therapy meeting in Seattle. "The 'cure' is that you eat an artificial diet of medical food. It's a liquid and doesn't taste very good, and there's not much you can do to disguise the taste.
"We're interested in advancing gene therapy because the potential is that a single treatment would last a lifetime or at least a significant number of years," said Laipis, a professor of biochemistry and molecular biology who is affiliated with UF's Genetics Institute and Powell Gene Therapy Center.
Laipis estimated that human trials of the experimental approach are several years away. PKU, which stands for phenylketonuria, results from a deficiency or complete absence of a specific enzyme that is necessary to convert the amino acid phenylalanine - found in all types of protein - into another amino acid, tyrosine. A buildup of phenylalanine is toxic to the central nervous system, particularly the brain.
Because infants with the disease face an extremely high risk of mental retardation if not treated, all babies in the United States and many other countries are screened for the disorder shortly after birth. Retardat
Contact: Victoria White
University of Florida