For children like 4-year-old Ryan Foust of Chesapeake, a drop or two of blood pricked from his heel when he was born was much more than just something to cry about.
The “heel stick” – as nurses call it – usually brings a startled cry from newborns, and Ryan was no exception.
But what that little drop of blood revealed in his newborn screening test had a profound effect on his life.
Ryan, it turned out, has phenylketonia.
PKU, as it is best known, is found in only about one of every 25,000 newborns. It is a recessive gene disorder that can have disastrous outcomes if not treated within the first weeks of life. So, most states include it in mandated newborn screening.
Ryan’s parents – Mike and Oanh Foust – learned within days of his birth in North Carolina that he was the one in 25,000. Both parents are nurses, but they never expected this diagnosis when their otherwise healthy baby boy was born.
“The dietitian at the hospital in Chapel Hill called us to meet with her right away,” Oanh (pronounced Wan) recalls. “We were shocked. But we were very grateful in the months after that because catching PKU right away helped us do everything right from the start.”
In PKU, the enzyme is missing that converts phenylalanine (an amino acid in protein) to tyrosine, which is essential for growth. When infants with PKU begin to eat foods containing natural protein, they develop irreversible symptoms, such as a small head, seizures, mental retardation, hyperactivity and decreased growth. Avoidance of protein is essential, with phenyl-free supplements used to replace natural protein to ensure normal growth and development.
For Ryan and other children with PKU, the diagnosis means a lifetime of diet control, primarily avoiding protein. Since the Fousts moved to Hampton Roads nearly two years ago, they have brought Ryan to Children’s Hospital of The King’s Daughters, where a medical geneticist, nurse practitioner and clinical dietitian closely monitor his progress during clinic visits every three months. They help his family manage his intake of proteins and monitor his phenylalanine every two weeks.
Ryan’s diet is very restrictive, said CHKD dietitian Melody Persinger. “He’s allowed only fruits, vegetables and special-order protein foods, plus a metabolic formula. He can have only five or six grams of protein a day, as compared to 30 or 40 for other children.”
With his bright eyes, cheery personality and normal growth record, Ryan is a living example of the importance of newborn screening, a pet subject of CHKD medical geneticist Virginia Proud. For the Fousts and the several other PKU families who depend on her for primary care at CHKD, Dr. Proud says there can never be enough emphasis on newborn screening. “Diseases tested for in newborns are often treatable by special diets and medications,” she said. “Early detection can help spare families much grief by preventing mental retardation, other disabilities and even death.”
“It’s hard to imagine what could have been Ryan’s future,” his mother said. Their other son, Matthew, 7, does not have PKU. “Fortunately, we all love vegetables, especially cooked Vietnamese style. And because Ryan needs proteins for growth, we buy special products and supplements that have no phenylalanine.”
“Ryan can’t have the meat or dairy products we eat, but he likes the phenyl-free substitutes his mother uses,” said his dad, who is an ensign in the Navy Nurse Corps stationed at the Naval Medical Center, Portsmouth. “He has his own special ice cream and milk, and he never has a problem when we say he can’t have something.”
Living in a region with a children’s hospital is very important to his family, Mike said. “We were referred to CHKD from the naval hospital soon after we arrived here, and we’ve felt well supported with Ryan’s care ever since.” Oanh works part-time as a nurse at CHKD and has regular contact with the genetics staff there.
The Fousts also believe it is important for families of PKU children to band together. “We’ve formed a support group, and I gave a cooking demonstration at our church,” Oanh said. They’re also working to raise awareness of PKU and the importance of newborn screening.
“The more other people know, the better chance Ryan has of having a normal life,” she said.
Dr. Proud practices with Children’s Specialty Group PLLC at CHKD.