Phenylketonuria (PKU) Screening

Phenylketonuria (PKU) is a genetic disorder characterized by the inability of the body to break down an amino acid called phenylalanine (Phe). PKU screening is a test used to detect this condition in newborns.

Purpose of PKU Screening

The primary purpose of PKU screening is to identify infants with PKU early, so that treatment can be initiated promptly to prevent intellectual disability and other complications associated with the disorder.

How PKU Screening is Performed

PKU screening is typically performed using a blood test, which involves pricking the heel of the newborn to collect a few drops of blood. The blood sample is then sent to a laboratory for analysis.

Types of Tests Used for PKU Screening

There are two main types of tests used for PKU screening:

• Guthrie test: This is a bacterial inhibition assay that measures the level of phenylalanine in the blood.
• Tandem mass spectrometry (MS/MS): This is a more sensitive and specific test that can detect multiple amino acid disorders, including PKU.

Interpretation of Results

The results of the PKU screening test are usually reported as follows:

• Normal: The level of phenylalanine in the blood is within the normal range, and no further testing is needed.
• Abnormal: The level of phenylalanine in the blood is elevated, and further testing is required to confirm the diagnosis.

Follow-up Testing

If the initial screening test is abnormal, follow-up testing may include:

• Repeat blood test: To confirm the results of the initial test.
• Genetic testing: To identify the specific genetic mutation responsible for PKU.
• Clinical evaluation: To assess the infant's overall health and development.

Treatment and Management of PKU

If a diagnosis of PKU is confirmed, treatment typically involves:

• Dietary restriction: Limiting the intake of phenylalanine-containing foods and supplements.
• Specialized formula: Using a formula that is low in phenylalanine.
• Regular monitoring: Regular blood tests to monitor the level of phenylalanine in the blood and adjust treatment as needed.

Importance of Early Detection and Treatment

Early detection and treatment of PKU are crucial to prevent intellectual disability, seizures, and other complications associated with the disorder. With proper management, individuals with PKU can lead healthy and normal lives.

Frequently Asked Questions (FAQs)

What is PKU screening?
A blood test to check for Phenylketonuria, a genetic disorder.

Why is PKU screening done?
To detect PKU in newborns and prevent brain damage.

When is PKU screening typically done?
Within the first few days of life, usually 24-72 hours after birth.

What is being measured in PKU screening?
Phenylalanine levels in the blood.

What are the consequences of untreated PKU?
Brain damage, intellectual disability, and seizures.

Is PKU screening mandatory?
Yes, in many countries, it is a part of routine newborn screening.

How is the blood sample collected for PKU screening?
Through a heel prick or from a vein.

What if the PKU screening result is positive?
Further testing and consultation with a healthcare provider are needed.

Can PKU be cured?
No, but it can be managed with a special diet and lifestyle changes.

Is PKU inherited?
Yes, it is an autosomal recessive genetic disorder.