National Standards Issued for Diagnosing, Treating PKU
According to Bessman, the panel's recommendations largely ignore the fact that some patients with PKU never develop mental retardation. They also ignore the fact that treatment of PKU can itself have harmful effects, and that the most commonly used diagnostic test for PKU is not 100% accurate, he says.
"My fear is that they are making suggestions based on numbers that are not wholly accurate," he tells WebMD.
The current treatment for PKU involves putting patients on a diet that excludes all high-protein foods, such as milk, eggs, and nuts. The reason is that all protein contains phenylalanine. When a strict diet is begun early and phenylalaline levels are controlled, experts believe that children with PKU can develop normally.
But the treatment itself can be dangerous and difficult to maintain since it also requires the diligent use of supplements, Bessman says. And due to the limited amount of research conducted on PKU, there's no evidence to demonstrate that everyone needs treatment or that mandatory screening is necessary, he tells WebMD.
PKU is thought to occur in about one in every 15,000 children, he says. That means the average hospital will see one case every four years, and the average pediatrician will see about one case during his or her lifetime, he says.
Still, the panel has full confidence in its recommendations, says Rodney Howell, MD, the panel chair and the chair of pediatrics at the University of Miami School of Medicine.
"The bottom line is that the average IQ of someone left untreated is 19," he tells WebMD. In essence, that means about 98% of people with PKU would require institutionalization if they were not treated, he says. Patients who are put on the diet generally go on to live normal lives, doing everything from attending college to raising families, he says.
"There is no question that the treatment has been remarkably effective," Howell says.
As for mandatory screening, "it's the best buy in the world," Howell says. At a cost of about $1.50 per test, it provides peace of mind, he says. It also ensures that people with PKU are diagnosed within the first few days of their lives, so precautions can be taken at a time when the damage to their brains could otherwise be substantial.