What is PKU?


PKU stands for phenylketonuria, a recessive hereditary disease caused by the bodyís failure to oxidize an amino acid (phenylalanine) to tyrosine, because of a defective enzyme.


How is PKU treated?


After a child is diagnosed with PKU, he or she is immediately placed on a low-protein diet. Instead of regular formula, a baby must drink a special formula which has phenylalanine removed. The person with PKU will continue to drink a similar formula (about 24 to 32 ounces per day) for the rest of his or her life. The formula is nearly nutritionally complete except for calories and the small amount of phenylalanine needed for growth.


The child or adult with PKU must measure all foods in order to restrict the amount of phenylalanine eaten. No meat, fish, eggs, nuts, or soybeans are allowed, and only limited amounts of dairy and vegetables. Most of an adultís calories come from the formula and from low-protein vegetables, fruits, and special low-protein processed foods made from finely milled grains.


After the age of three, there is no danger of permanent brain damage, but if the diet is not followed, the child or adult may suffer significant developmental delays, learning disabilities, attention problems, short-term memory loss, stunted growth, and nutritional deficiencies. The formula and the low-protein foods are very expensive, but the state of Indiana only requires insurance coverage for the formula.


What can research accomplish?


Current research is focused on replacing the missing enzyme for metabolizing phenylalanine, genetically altering PKU patients so their liver will make the enzyme, or genetically altering natural protein sources so that they will not have as much phenylalanine.