by Laura Hermes


Phenylketonuria (PKU) is a birth defect that causes an amino acid called Phenylalanine to build up in the blood. PKU is caused by a mutation in a gene that helps create the enzyme needed to break down phenylalanine.

How it is Diagnosed

PKU is an inherited disorder of metabolism and causes an increase of phenylalanine in the blood (it comes from the diet and produces proteins). It is found in all foods and some artificial sweeteners. It can cause cognitive disorder and other serious problems. It can be determined at birth through newborn screening.


PKU is caused by a build up of phenylalanine in the blood. PKU is a genetic disorder caused by a recessive gene.


PKU has a range from mild to severe. If a child is born with PKU and does not undergo treatment of a low phenylalanine diet, infants will develop cognitive disorder and/or behavioral problems. Other symptoms include seizures, developmental delay, and autism. A person with PKU also might have a lighter skin tone and hair color than other family members.


The treatment for PKU would be to limit the amount of protein in a diet, but a person with PKU must remain on this diet for the rest of his/her life.


Students with PKU can be in a regular class with other students, and except for a special diet, they are just like any other student. Not staying on the diet may result in cognitive disorder in which case the student will be moved into a different class.


The PKU support group here in Texas is "North Texas PKU Association"