Phenylketonuria

Overview

Phenylketonuria (PKU) is a rare inherited disorder that causes an amino acid called phenylalanine to build up in the body due to a lack of the enzyme needed to break it down. This can lead to serious health problems if left untreated. People with PKU need to follow a diet that limits phenylalanine, which is found mostly in protein-containing foods. Without treatment, PKU can cause symptoms such as a musty odor in the body, nervous system problems, skin rashes, lighter skin and hair color, and intellectual disability. PKU is typically diagnosed in newborns through screening programs and, if detected early, can be managed effectively with a restricted diet and possibly medication.

Understanding the disease

Symptoms

Phenylketonuria (PKU) is a genetic disorder that affects the body's ability to break down an amino acid called phenylalanine. Symptoms of PKU can include:

1. Extreme fatigue
2. Weakness
3. Pale skin
4. Chest pain, fast heartbeat, or shortness of breath
5. Headache, dizziness, or lightheadedness
6. Cold hands and feet
7. Inflammation or soreness of the tongue
8. Brittle nails
9. Unusual cravings for non-nutritive substances, such as ice, dirt, or starch
10. Poor appetite, especially in infants and children with iron deficiency anemia
11. Loss of appetite and weight loss
12. Joint and muscle pain
13. Abdominal pain and gastrointestinal bleeding
14. Weakness, fatigue, or a general feeling of being unwell
15. Rash or skin sores
16. Pain, numbness, and tingling in the hands and feet It is important to note that PKU symptoms can vary from person to person and may not be present in all cases. A diagnosis of PKU is usually made through newborn screening or through testing if symptoms are present. Treatment typically involves strict adherence to a low-phenylalanine diet, which requires careful monitoring and management.

Development

Phenylketonuria (PKU) can develop in different ways, depending on the severity of the condition. PKU can be mild, moderate, or severe, and the symptoms and severity can vary from person to person. PKU is caused by a gene change (genetic mutation) that affects the production of the enzyme phenylalanine hydroxylase (PAH). This enzyme is necessary for the proper breakdown of the amino acid phenylalanine. When PKU is not well-managed, phenylalanine can build up in the body, leading to potential health problems. Severe PKU can result in mental and behavioral issues, while milder forms may not cause significant symptoms. It is essential to follow a restricted diet to manage PKU throughout a person's life to prevent the buildup of phenylalanine and related health complications.

Assessment and Diagnosis

Triage

You should see a doctor if phenylketonuria is suspected during pregnancy or if routine newborn screening tests show that a baby may have PKU. Women with a history of PKU should also consult their healthcare provider before becoming pregnant and during pregnancy to reduce the risk of harming their unborn babies. It is important to follow your healthcare provider's guidance and treatment plan if you have PKU or suspect that you or your baby may have it.

Diagnosis

Phenylketonuria (PKU) can be diagnosed through newborn screening. In the United States, all 50 states require newborns to be screened for PKU. A blood test is done on a day or two after the baby's birth, after the baby is 24 hours old and has had some protein in the diet. The blood sample is tested for certain metabolic disorders, including PKU. If you or your family have a history of PKU, your healthcare provider may recommend screening tests before pregnancy or birth.

Management and Treatment

Treatment

Phenylketonuria (PKU) is a rare inherited disorder that requires lifelong management. The primary treatment for PKU involves following a strict diet that limits or reduces phenylalanine, an amino acid found mostly in protein-rich foods. Newer medications may allow some people with PKU to eat a diet that has a higher or unrestricted amount of phenylalanine. It's essential to work closely with healthcare providers to determine the most appropriate treatment plan based on individual needs and severity of the condition. Regular check-ups and monitoring of blood phenylalanine levels are necessary to ensure that the treatment plan is effective.

Preparing for medical consultation

To prepare for an appointment for phenylketonuria (PKU), you should:

1. Bring a family member or friend along for support and to help remember important information.
2. Make a list of questions to ask your health care provider and dietitian.
3. Write down your symptoms, including when they started and how they have changed over time.
4. Take a list of all medications, vitamins, or supplements you are taking.
5. Write down your key medical information, including any other diagnosed conditions.
6. Prepare a detailed description of your typical daily diet.
7. Be aware of any pre-appointment restrictions, such as not eating solid food on the day before your appointment. During the appointment, you can expect your healthcare provider to ask questions about your child's symptoms, medical history, and family medical history. They may also perform tests to diagnose PKU and provide guidance on managing the condition. Remember to ask any questions you may have during the appointment to ensure you have a clear understanding of your child's diagnosis and the recommended course of action.