National Standards Issued for Diagnosing, Treating PKU
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.
But further research is needed concerning the roughly 2% of patients with PKU who do not develop mental retardation despite not being treated, Howell concedes. States also should be encouraged to keep better data to aid in the development and testing of new treatments, and health officials should be encouraged to treat the diet as a medical necessity so that families can defray the costs, he says.
New treatment options are being studied, and experts believe there may someday be a genetic treatment to replace the diet. In the meantime, despite some doctors' reluctance to sign on, the standards are likely to be adopted by many pediatricians and states, Howell says.
Physicians are not bound by the standards, but studies done before and after other consensus conferences have shown that they can affect the diagnosis, treatment, and management of diseases and disorders, he says. Such standards also can influence insurance reimbursement policies, thus indirectly affecting doctors' behavior.
"We hope very much that it will have an impact," says William Rizzo, MD, a member of the panel and a professor of pediatrics and human genetics at the Medical College of Virginia in Richmond.