The researchers found in their unprecedented 25-year study that prompt diagnosis coupled with a rapid start of intravenous drug therapy significantly improves the survival rates of people with the condition, called urea cycle disorders. The condition affects proteins in the liver that are necessary to process the by-products of protein metabolism.
"Historically, the prognosis for patients with urea cycle disorders has been universally poor," said Gregory Enns, MD, director of the biochemical genetics program at Packard Children's. "To now be able to talk about the potential for normal outcomes is pretty remarkable."
Enns, who is also associate professor of pediatrics at Stanford's School of Medicine, collaborated with researchers from the Johns Hopkins School of Medicine, the University of Minnesota, Thomas Jefferson University and the Medical College of Wisconsin on the study, which will be published in the May 31 issue of The New England Journal of Medicine. Enns is the lead author of the study, and Hopkins researcher Ada Hamosh, MD, is the senior author.
Urea cycle disorders affect about one in every 8,200 people, but the diagnosis is often missed or delayed. The study took 25 years to accumulate enough patients to evaluate the drug treatment.
People with urea cycle disorders are unable to convert
nitrogen-rich ammonia, a normal by-product of protein metabolism,
into urea that is excreted by the body as urine. Mutations in
several different proteins can short-circuit the urea cycle, which
occurs in the liver, but the result is the same: escalating levels
of blood nitrogen cause irreversible brain d