Does your baby have PKU? (Phenylketonuria) - Let's talk about this in detail!

Are you a mother of a newborn baby? Or have you heard that someone in your family or a friend's child has this condition? If so, this article will be very important for you. Today we are going to talk about Phenylketonuria , or PKU for short, a condition that many people have heard of and are not used to, but is very worth knowing. Don't worry, we will talk about this simply, in a way that you can understand.

What is PKU (Phenylketonuria)? Let's understand it simply!

Simply put, PKU is a genetic condition . That is, it is caused by a small change in our genes. This causes our body to not properly handle a substance called phenylalanine .

Now you're probably wondering what phenylalanine is. It's an amino acid . Amino acids are like little building blocks that help make proteins. Phenylalanine is found in many of the foods we eat, especially those high in protein. It's also found in some artificial sweeteners, such as aspartame .

Normally, in a healthy person, this phenylalanine is broken down to the required amount and processed in a way that the body can absorb it. However, in a person with PKU, this process does not happen properly. Then, this phenylalanine starts to accumulate in the body. It is like a clogged pipe in a water tank that fills with water. This accumulation is what causes problems. In particular, it can affect brain development . If left untreated, conditions such as `intellectual disability` may occur.

Are there different types of PKU?

Yes, there are several types of PKU, depending on the severity. Symptoms also vary depending on the type, especially in those who do not receive treatment.

Three main types can be identified:

• Classic PKU: This is the most severe form.
• Moderate or mild PKU: This is a little less severe.
• Mild hyperphenylalaninemia: This is the least severe form of the condition. Even without treatment, these people have a very low risk of developing intellectual disability.

Who is most affected by this PKU condition?

Because PKU is genetic, anyone with mutations in both copies of the PAH gene can develop the condition. Some studies suggest that people of Native American or European descent are at slightly higher risk.

Another important thing is that a pregnant mother who has uncontrolled PKU, that is, very high levels of phenylalanine in her blood, can have problems with the baby's intellectual development, birth defects, and other problems, even if her baby does not have PKU . Therefore, controlling PKU during pregnancy is very important.

How common is PKU?

According to statistics from countries like the United States, PKU affects about one in 10,000 to 15,000 newborns. Although it is difficult to find exact statistics on this in Sri Lanka, this condition can be seen anywhere in the world.

What are the symptoms of PKU? Don't panic, know this!

In many countries, including some hospitals in Sri Lanka, newborn screening is already performed on newborns to determine if they have PKU, making it possible to identify the condition before symptoms appear. Therefore, the incidence of symptoms is currently very low.

However, if this condition is not recognized in some way or if it is not treated, some symptoms may appear. These are:

• Skin diseases like eczema .
• Changes in skin and/or hair color ( skin and hair becoming lighter than other family members).
• Head size smaller than normal (microcephaly) .
• A musty odor from the breath, skin, or urine. It smells like something old.

The most severe symptoms that can occur if left untreated are:

• Behavioral problems .
• Developmental delays - This means that a baby's developmental milestones, such as smiling, holding their head up, and walking, are delayed.
• Intellectual disabilities .
• Rarely, seizures such as epilepsy may occur.

Important: Remember, many of these symptoms only occur if left untreated. Nowadays, newborn screening can detect this early, so there is nothing to worry about.

What is the real cause of PKU?

The main cause of PKU is a mutation in both copies of the PAH gene in our body. This PAH gene instructs our body to make an enzyme called phenylalanine hydroxylase . This enzyme converts the amino acid phenylalanine, which we eat, into proteins that the body can use.

So, when this PAH gene is not working properly, the enzyme is not produced, or it is not working properly. Then, phenylalanine from food accumulates in the body. Our body, especially the brain, is very sensitive to excess phenylalanine. That is why the brain can be damaged.

How is PKU transmitted through genes?

PKU is a genetic condition that is inherited from parents to children in an autosomal recessive pattern . While this may sound like a bit of a scientific term, it simply means:

Imagine, the gene that causes PKU is called "p". The healthy gene is called "P".

To develop PKU, a child must receive a "p" gene from both the mother and the father (that is, it must be "pp").

In many cases, parents can be carriers of this PKU gene. That means, they can have the gene as "Pp". They don't have the symptoms of PKU, because the healthy "P" gene is working. But, they can pass that "p" gene to their children.

So, if both parents are carriers (Pp x Pp), when they have a child:

• There is a 25% chance that a child will develop PKU (pp).
• There is a 50% chance that the child will be a carrier (Pp) - no symptoms.
• There is a 25% chance that the child will receive both healthy genes (PP) - no PKU, and not be a carrier.

That's why it's something that needs to come from both parents.

How do you know if you have PKU?

Most often, PKU is diagnosed through a newborn screening test, which is done between 24 and 72 hours after a baby is born . This involves pricking the baby's heel with a small needle and taking a few drops of blood . This checks the level of phenylalanine in the baby's blood.

• If the baby's blood levels of phenylalanine are found to be high, doctors will do further tests (blood or urine tests) to confirm the PKU condition, as well as find out what type of PKU it is.
• Because PKU is a genetic condition, a genetic test can be performed to determine the exact gene mutation responsible for the symptoms.

If newborn screening tests are not done, PKU can be detected at any age, but the earlier the detection, the better.

What treatments are available for PKU?

Treatment for PKU is a lifelong process. But don't worry, if it's managed properly, you can live a healthy life. Treatment may include:

1. Special diet: This is the most important thing. You need to eat a diet that is low in phenylalanine but rich in other nutrients .

2. Vitamins, minerals, and nutritional supplements: These are necessary to get the nutrients you need, as dieting can lead to missing out on some nutrients.

3. Medication: Some people may be given a medication like sapropterin dihydrochloride (Kuvan®) . This helps the body break down phenylalanine.

4. Pegvaliase (Palynziq®): People who take this medication can eat normally without the need for a special diet. It replaces the enzyme that breaks down phenylalanine that is not working properly in people with PKU.

If you or your child has PKU, you should work with your doctor and a dietitian to develop the best treatment plan.

What foods contain phenylalanine? Let's be aware of these!

People with PKU (unless they take a medication called `Pegvaliase`) need to limit foods high in phenylalanine. These are found most in protein-rich foods. For example:

• Milk and milk products (cheese, yogurt)
• Eggs
• Nuts (like peanuts, cashews)
• Fish
• Chicken
• Beef
• Legumes like beans and lentils
• Aspartame, an artificial sweetener (may be found in some sugar-free drinks and foods)

Is there a special diet for someone with PKU?

Yes, absolutely. A person with PKU (not taking the drug `Pegvaliase`) should follow a low-protein diet . High-protein foods such as meat, fish, eggs, and dairy products should be reduced as much as possible, or stopped completely.

But this is not as easy as it seems. Because protein is essential for the body. Therefore, it is very important to talk to a doctor or dietitian and create a balanced diet that provides all the other nutrients the body needs. There are special formulas for babies with PKU, which are low in phenylalanine, but still contain other necessary nutrients.

Imagine, you have a little baby at home with PKU. How careful do you have to be about the food you feed him? You have to look at every food package and find out how much phenylalanine is in it. It's a big sacrifice, but it's worth it for the child's future.

Can PKU be prevented?

Because PKU is genetic, there is no way to prevent this condition from occurring.

However, if you are planning to get pregnant, you can undergo genetic counseling and carrier screening to find out if you and your partner carry the PKU gene. This will help you understand your risk of having a child with PKU.

What kind of future can someone with PKU expect?

This is a problem that many people have. Although PKU is a lifelong condition, if managed properly, most people can live healthy, normal lives.

• After diagnosis, regular blood tests are needed to check the phenylalanine level in the blood . This is how you can determine if the diet is being followed properly and if the medication is working properly.
• For those on a diet, it's very helpful to work closely with a dietitian . They can tell you exactly what foods to eat, what to avoid, and how to get the nutrients your body needs.
• If a woman with PKU becomes pregnant, her doctor and nutritionist will work together to create a special diet plan that will ensure that the mother gets the nutrition she needs while minimizing any potential harm to the baby.

How can I protect myself/my child from PKU?

A PKU diagnosis is a lifelong condition, so it is important to stay in regular contact with your doctor and monitor your blood phenylalanine levels.

• If you are on a diet, take the necessary vitamins and supplements to make up for the protein deficiency.
• Follow this diet for the rest of your life. Otherwise, symptoms may recur and become dangerous to your health.
• If you are thinking about starting a family, talk to your doctor about genetic testing , which can help you understand your risk of having a child with PKU.

When should you see a doctor?

• If you or your child develops symptoms related to PKU (the ones we discussed earlier), see a doctor immediately for a complete examination.
• Before you get pregnant, or early in your pregnancy, you can ask your doctor about carrier screening , which can help you and your partner find out if you are at risk of having a child with PKU.
• If you have PKU, see your doctor regularly for blood tests and monitoring.

What questions should I ask my doctor?

If you have questions about PKU or your child's PKU status, don't be afraid to ask. Here are some examples:

• " How can I make sure my baby is getting the right nutrition to stay healthy?"
• "Do I/my child need to take any additional vitamins or nutritional supplements?"
• "Is a low-protein diet enough to reduce my/my child's phenylalanine levels, or do I need to take medication as well?"
• "What things should I be careful about when preparing this special meal?"
• "If a child is going to school, how should the school be informed about their food and drink?"

At first, choosing foods that are free of phenylalanine can be a little difficult, but as you work with your doctor and nutritionist, you'll get used to it.

Finally, some important things to remember (Take-Home Message)

Although PKU is a lifelong condition, it can be successfully managed. The key is to identify it early and manage it properly.

• Newborn screening is very important. It can detect other diseases like PKU early.
• As soon as you find out you have PKU, be sure to seek medical advice and the guidance of a nutritionist .
• Strict adherence to diet and, if necessary, medication throughout life is essential for the healthy development of your or your child's brain.
• Monitor your phenylalanine levels with regular blood tests .
• You are not alone. Connecting with other people with PKU and their families can be a great source of strength and encouragement for you in support groups .
• If you are a parent of a child with PKU, teach your child to live with this condition with patience and love .

I hope this information has helped you gain a better understanding of PKU (Phenylketonuria). Remember, awareness is the best weapon against any health problem!

` PKU, Phenylketonuria, phenylalanine, genetic diseases, newborns, diet, low protein diet, newborn screening