Phenylketonuria (PKU)

In the United States alone 1 in every 25,000 babies is born with Phenylketonuria (PKU). PKU affects the creation of an enzyme designed to break down phenylalanine which is used to synthesize protein. Tests are available to detect the presence of Phenylketonuria before newborns leave the hospital.

How is Phenylketonuria transmitted?

PKU is an inherited condition and passed down when both parents also have it. The gene that is passed down is called Phenylalanine Hydroxylase (PAH). For a child to develop Phenylketonuria each parent must pass to them an abnormal PAH gene. It is possible to have one normal and one abnormal PAH gene and be a carrier but not be afflicted.

What happens to a child with PKU?

Children with Phenylketonuria will exhibit signs of apathy early on, often within the first 6 months to a year. As age progresses, this will appear to cause delayed maturation and lead to behavioral problems. Visible symptoms of PKU may be rash, dry skin, or even seizures. Ultimately, this buildup of phenylalanine can lead to brain damage, retardation, or even death.

Testing for PKU

Before newborns leave the hospital, a device is used to make a slight incision in the heel and a drop of blood is drawn onto test paper. This is then sent for laboratory testing. If preliminary tests indicate the presence of Phenylketonuria additional blood and urine screening is done to verify results.

PKU symptoms are treatable through a restricted diet that is low in Phenylalanine. Affected children will need to follow this regimen up through adolescence and early adulthood at a minimum. As of 2007, medical treatments have been developed to help manage symptoms as well but research is ongoing.