What is phenylketonuria (PKU)?
Your newborn needs to be screened for phenylketonuria. When the condition is detected early, treatment can prevent developmental delays and intellectual disabilities.
It may seem minor, but a simple prick of a baby's heel during the first week of life may help prevent brain damage months later.
The heel prick is to draw a sample of blood and test it for phenylketonuria (PKU), an inherited body-chemistry disorder that causes developmental delays and intellectual disabilities if left untreated.
All states routinely screen newborn babies for PKU. The test is highly accurate when performed on infants between the ages of 1 and 7 days.
What is PKU?
Children with PKU cannot properly process the protein phenylalanine, which then builds up in their bloodstream and causes brain damage.
If PKU goes untreated, the child may appear normal for the first few months of life. But the child will eventually lose interest in his or her surroundings, and will be clearly disabled by age 1.
According to the Eunice Kennedy Shriver National Institute of Child Health and Human Development, other symptoms of PKU include:
- Restlessness and seizures.
- Small head size.
- Stale, unpleasant skin odor.
- Behavioral problems.
- Dry skin or rashes.
Who gets PKU?
PKU is inherited. Even if someone doesn't have the disease, he or she can carry the gene and pass it on to a child.
Both parents have to carry the PKU gene for their child to inherit the disease, according to the March of Dimes.
If only one parent passes the gene on to his or her child, the child will not have the disease but will carry the PKU gene.
About 1 out of every 10,000 to 15,000 babies in the United States is born with PKU each year, according to the March of Dimes.
How is PKU treated?
Damage from PKU can be completely prevented if the disease is detected and treated at an early age.
Treatment for PKU involves a special diet that starts during the first three weeks after birth and continues for the rest of the child's life, according to the March of Dimes. The child's doctor develops an individual eating plan that changes as the child grows.
Babies with PKU are fed a special protein formula with reduced phenylalanine. Breast milk, which also contains phenylalanine, should be used sparingly, according to the March of Dimes.
Older children need a diet that is low in phenylalanine, including some vegetables, fruits, cereals and noodles. Older kids should avoid high-protein products—such as regular milk, cheese, eggs, meat and fish. Diet drinks and foods that contain the artificial sweetener aspartame—such as NutraSweet and Equal—should also be strictly avoided.
Because children need protein to grow normally, they must continue to drink a special formula that is high in protein and contains little or no phenylalanine.
People with PKU should get their blood tested regularly to find out if their levels of phenylalanine are too high or too low. With the help of a doctor, people with PKU should then adjust their diet.
PKU and pregnancy
Women with PKU who plan on having babies should be on a special diet before conception and throughout their pregnancy. If pregnant women have too much phenylalanine in their blood, chances are high that their babies will be born with brain damage—which cannot be helped by the PKU diet.
Learn more
For more information about PKU, visit the March of Dimes website.
Reviewed 4/26/2024