Rare genetic disorder leads Holladay family to healthy eating habits

Published: Sunday, Dec. 2 2012 5:25 p.m. MST

Seth Oliver, 3, has a banana for a snack while his mother has her pen ready to jot it down in his notebook at their Holladay home Friday, Nov. 30, 2012. Seth and his sister, Claire, have phenylketonuria, or PKU, a rare genetic disorder that affects a person's ability to process an important part of protein called phenylalanine.

Laura Seitz, Deseret News

HOLLADAY — Making sure kids eat their vegetables is hard enough for some moms, but watching, weighing and measuring every morsel of everything they eat is another story.

"I know every bite of food my kids have eaten, every day of their lives," said Amy Oliver, a Holladay mother of three and part-time attorney. Two of her kids require extra attention, but one wouldn't know it just by looking at them.

"The only way you can tell is if you watched them eat, and even then, if you watched carefully," she said.

Claire, 5, and 3-year-old Seth Oliver have phenylketonuria, or PKU, a rare genetic disorder that affects a person's ability to process an important part of protein called phenylalanine. They are two of about 92 children and hundreds of adults in Utah who are diagnosed with the very rare condition, which requires scrupulous note taking on the only known treatment — a special diet for life.

Over the years, Oliver has grown accustomed to subtracting the weight of the small, color-coded plastic dishes she uses to serve the kids, the leftover peels from various foods, and whatever food her children don't eat, all the while meticulously calculating the results to get the amount of protein each child has received each day.

Claire and Seth each need about 22 grams of protein, or 1,500 milligrams of "phe" each day in order to be healthy. The amount won't change much as they get older or as they grow bigger, but it has to be monitored to prevent dangerous side effects, including irreversible brain damage and behavioral issues.

Oliver and her husband have an older son, Luke, who didn't receive the mutant gene from each of his parents and therefore can eat a normal diet.

One in 50 adults are carriers of PKU, and every person carries up to 50 defective genes that could be passed on to their children, said Dr. Nicola Longo, a professor and the chief of the division of medical genetics at the University of Utah.

There's a one in 2,500 chance that two adults who each carry the gene will come together to have a child with the metabolic disorder, and the odds are one in four for each pregnancy, he said. One in 15,000 children are born with the condition, and it is typically caught within the first week of life.

Newborn screening, in which a tiny amount of blood is drawn from the heel of a baby, checks not only for PKU, but for about 37 other metabolic disorders. The two-test series is less than $100 but critical for proper development, Longo said.

"If you find out later, the child might be dead or have irreversible mental disabilities," he said. "If you wait for symptoms, it is just too late."

Symptoms are evidenced in delayed achievement of normal developmental milestones, as the brain fails to grow. Delayed diagnosis and treatment can lead to mental retardation and other neurological problems, such as memory loss and mood disorders.

Longo said newborn screening — the first test of which is performed within 72 hours of birth, and the second between 7 and 21 days of age — has been conducted in the United States and Europe for the past 40 or more years. It was initiated in 1963 and mandated by law in the U.S. in 2008. Unless parents opt out, it is routinely conducted, saving lives and brain function, Longo said.

He said, however, there are still patients who are diagnosed later in life with PKU after mental disabilities arise because they were not diagnosed at birth.  Those individuals, Longo said, are often institutionalized and cannot live normal lives.

Adults who do not follow the stringent diet can slip mentally, including loss of various executive functions. Longo said the effects are reversible if a person returns to the diet, but that is easier said than done.

Try out the new DeseretNews.com design!
try beta learn more
Get The Deseret News Everywhere