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- Is PKU serious?
- Is PKU curable?
- What is "Phe"?
- How do you get PKU?
- Did I cause my child's PKU?
- What exactly is PKU?
- How is PKU managed?
- What are the symptoms of PKU?
- How do I learn to properly manage PKU?
- What if I don't regulate the diet closely?
- Tell me about the Phe-free formula.
- How long do you have to stay on the restricted diet?
- What can happen if you go off the diet?
- Are people with PKU more at risk for attention deficit hyperactivity disorder (ADHD)?
- What is a metabolic clinic?
- How often does a person with PKU need Phe blood tests?
- What's the difference between classic PKU and moderate PKU?
Q: Is PKU serious?
A: Yes, PKU, or phenylketonuria (pronounced fen-il-Key-to-New-ree-uh), is serious. If it is not managed from birth, PKU can cause mental retardation. Later in life, it can cause many other problems, like a loss of intelligence (IQ), depression, and being unable to focus. People with PKU can grow up happy and healthy with the right care.1 Learn more
Q: Is PKU curable?
A: Currently there is no cure for PKU. The disease is managed for life with a special treatment program that can lower the level of an amino acid called "phenylalanine" or "Phe" in the body. This begins with a low-Phe diet.1,2 Some people also respond to a medicine that can help lower Phe levels in people with PKU.14 With careful management, people with PKU can look forward to healthy and fulfilling lives.2 Learn more
Q: What is "Phe"?
A: Phenylalanine, or "Phe" is an amino acid. It is one of the building blocks of protein, and is found in almost all foods. There is lots of Phe in meat, dairy, and other protein-rich foods. Vegetables, fruits, and some grains have much less Phe.15 Learn more
Q: How do you get PKU?
A: PKU is inherited. Both parents have to carry the PKU gene in order for a child to be born with PKU.
You can carry the PKU gene but not have PKU yourself. If you and your partner both carry the gene but don't have PKU, each child you have has a chance of having PKU.
Both parents must carry the PKU gene for their child to have PKU. If you have PKU but your partner does not, your child is unlikely to have PKU.1
Q: Did I cause my child's PKU?
A: PKU is inherited. But parents are not to blame for their child's PKU. There is nothing that either parent did prior to or during the pregnancy to cause PKU.1
Q: What exactly is PKU?
A: PKU belongs to a class of diseases that doctors call "inherited metabolic diseases," or "inborn errors of metabolism." In these diseases, the body can't do certain chemical processes required for normal growth and development.2
For people with PKU this means that a certain enzyme is broken.1 Usually, the body uses the enzyme to break down an amino acid called phenylalanine, or Phe. Once Phe is broken down, the body uses it to make another amino acid called tyrosine.1
In people with PKU, the enzyme doesn't work to break the Phe down into tyrosine. Phe builds up in the body and brain. While a certain amount of Phe is essential for normal growth and development, too much Phe in the brain causes damage, particularly in very young children.1 Learn more
Q: How is PKU managed?
A: The key to PKU management is keeping the amount of Phe in the blood within a safe range. The exact definition of a safe range is still widely debated.1
A person with PKU (or the parent of a young child with PKU) must record the amount of Phe eaten, restrict the diet to low Phe foods, and replace high Phe foods with low Phe alternatives. A person with PKU will have a Phe-free medical protein formula with most meals.1
Some people with PKU can also take a medicine that can help lower Phe.14
Q: What are the symptoms of PKU?
A. The symptoms of PKU are caused by high levels of Phe in the body. If untreated in childhood, these very high levels of Phe cause severe mental retardation. Even in babies and children who are treated, high levels of Phe may cause symptoms like being cranky or fretful, unable to focus, and anxious.16
In adults, when Phe levels are too high, problems can include:1,3,4,5
- Lower intelligence (IQ)
- Bad moods, being cranky or irritable
- Feeling "foggy"
- Thinking and responding slower
- Depression
- Feeling anxious
- Not being able to focus or pay attention
When PKU is managed well and Phe levels stay low, people with PKU can expect to lead healthy and fulfilling lives. By keeping blood Phe levels low, excess Phe will not accumulate in the brain to cause problems.
Q: How do I learn to properly manage PKU?
A. There is a lot of help available. Many experts and families who have handled PKU can help show you the way. You can work with a dietitian at a metabolic clinic who can help you decide what kind of diet is needed. That person can also give you tips for creating a good routine.1
You will find that many resources are available, including support groups and internet-based bulletin boards for communication with other people who are dealing with PKU. This website is a great place to start. Join the PKUniverse now.
Q: What if I don't regulate the diet closely?
A: If you are the parent of a child with PKU, you run the risk of your child having brain damage caused by high Phe levels. Your child may also have mood problems, social problems or problems focusing.
Maintaining a low blood Phe level is very important in young children, when the brain is most likely to be hurt by the bad effects of high Phe.
As a teen or adult, if you are not careful about your low Phe diet, you will most likely notice many of the symptoms of uncontrolled PKU. You may start to feel moody, foggy or anxious. You may have a hard time focusing or thinking clearly and quickly. This is because high Phe levels are toxic to the brain.1 Learn more
Q: Tell me about the Phe-free formula.
A: The PKU diet replaces meat, dairy and eggs with a special medical formula that does not contain Phe. This formula is prescribed by a doctor at a metabolic clinic. It may take the form of a powder mixed with drinks or as a premixed drink.2
Most of the calories a person with PKU eats come from this formula. The remaining calories, and all of the Phe that a person with PKU needs, come mostly from relatively low Phe foods such as grains, fruits and vegetables. Since most food contains some Phe, people with PKU must be careful about what–and how much–they eat.1,2
Q: How long do you have to stay on the restricted diet?
A: In 2000, the National Institutes of Health said that a person with PKU who needs the special diet should stay on it always. This is often referred to as the "diet for life."1,2
Q: What can happen if you go off the diet?
A: If a child goes off the diet very early in life (from birth to the elementary school years), he or she may suffer brain damage and loss of intelligence (IQ) that can never be fixed.
For a person who goes off the diet later in life, the symptoms may include:1,3,4,5,6
- Lower intelligence (IQ)
- Bad moods, being cranky or irritable
- Feeling "foggy"
- Thinking and responding slower
- Depression
- Feeling anxious
- Not being able to focus or pay attention
Q: Are people with PKU at higher risk for attention deficit hyperactivity disorder (ADHD)?
A: Studies show a higher risk for ADHD among children with PKU. The risk is higher for children whose Phe levels are not as well controlled.17 In PKU, the issue is more often trouble focusing (attention deficit) than hyperactivity.18
Studies show that teens and adults may also have more trouble focusing if Phe levels are higher than they should be.1
Q: What is a metabolic or PKU clinic?
A: The metabolic clinic specializes in diseases like PKU. It is where you will go for regular blood testing, formula prescriptions and dietary consultations.
When a newborn first tests positive for PKU, the results are sent to a lab at a local metabolic clinic to confirm a diagnosis and begin care. The staff at the metabolic clinic will help you manage PKU throughout life.
Q: How often does a person with PKU need Phe blood tests?
A: Your doctor will tell you. An infant or child may be tested often, while the clinic figures out the right diet to control their Phe levels. This may be as often as 1 or 2 times a week until Phe levels stabilize at a good level. After that, testing may be required once a month or so. Testing will likely continue for life.1
Q: What's the difference between classic PKU and moderate PKU?
A: PKU is divided into two types: classic PKU and moderate PKU. A person with moderate PKU will have lower blood Phe levels than a person with classic PKU, if both are eating the same diet.1,2
Both classic and moderate PKU patients can have brain damage if untreated. The damage is more significant in classic PKU.2
