1. Inheriting the PKU Gene
Phenylketonuria, or PKU, is an inherited disease. Both parents of a baby must carry the PKU gene in order for the baby to have it. A person with PKU is missing the enzyme phenylalanine hydroxylase. This enzyme converts phenylalanine into tyrosine. When a person has PKU, the body cannot process phenylalanine so toxic levels build up in the body. Phenylalanine is a part of the protein found in many foods including meat, wheat products and some fruits including oranges.
2. PKU Testing for Newborns
In most states, newborns undergo testing for PKU before leaving the hospital after birth. The test is a simple heel prick. If the test comes back positive, the doctor orders further tests, including more in depth blood tests and a urinalysis. Because elevated phenylalanine levels can cause mental retardation, brain damage and central nervous system damage within the first three to six months of life, PKU testing for newborns is essential to avoid these problems.
3. Special Diet Is Required
People with PKU must eat a very strict diet that is low in protein. This special diet should start within seven to 10 days after birth by giving the newborn a special formula that is phenylalanine-free. It's OK to supplement with breast milk if the baby can tolerate it. Children must stay on a diet that is free of meat, fish, milk and the artificial sweetener aspartame found in products such as NutraSweet. Children must take a phenylalanine-free formula to get necessary protein. Sometimes, under a doctor's supervision, adults can deviate from this strict program without harmful side effects.
4. Medical Treatment May Allow a More Normal Diet
Under certain conditions, such as in a person with variant or mild PKU, a doctor may try to treat them by using a prescription drug called Kuvan. In some cases, this drug can help a person to tolerate a more normal diet. There is no way of knowing in advance who will respond to this treatment. Gradually introduce new foods and your doctor will run tests frequently to monitor the phenylalanine levels in the blood. If a person doesn't respond to the drug, he may find it difficult to return to the restrictive diet after being able to try new foods.
5. Pregnancy and PKU
A woman who has PKU can have a normal pregnancy and a very healthy baby. At least three months prior to conception, the woman should go on a very strict low phenylalanine diet to avoid elevated phenylalanine levels in her blood that will affect the fetus. If a woman becomes pregnant without starting the diet prior to conception, she should start the diet no later than the eighth week of pregnancy to prevent possible problems. A woman who is considering pregnancy or is pregnant should see her doctor as soon as possible to determine the proper diet and treatment plan for her specific pregnancy needs.
