Phenylketonuria (PKU) is a rare genetic metabolic disorder that affects the body’s ability to break down phenylalanine (Phe), an amino acid found in protein-rich foods. Without proper treatment, phenylalanine builds up to toxic levels, leading to severe brain damage and intellectual disability.
📌 Fact: PKU is one of the first metabolic disorders detected through newborn screening, allowing for early dietary management and normal brain development.
🩺 What Is PKU and How Does It Affect the Body?
In people with PKU, a genetic mutation prevents the liver from producing enough of the enzyme phenylalanine hydroxylase (PAH), which is needed to break down phenylalanine into a harmless form. As a result:
❌ Excess phenylalanine accumulates in the blood and brain.
❌ High Phe levels cause toxic damage to brain cells.
❌ Without treatment, PKU leads to severe intellectual disability, behavioral problems, and neurological issues.
📌 Fact: PKU is an autosomal recessive disorder, meaning a baby must inherit two faulty genes (one from each parent) to develop the condition.
🚨 Why Is Newborn Screening for PKU So Important?
Newborn screening for PKU is essential because babies with PKU appear normal at birth but will develop severe symptoms within months if untreated.
🔹 Blood test is done within 24-48 hours after birth.
🔹 Measures phenylalanine levels to diagnose PKU early.
🔹 Allows immediate dietary treatment to prevent brain damage.
📌 Fact: Before newborn screening was introduced, PKU was a major cause of intellectual disability. Today, early diagnosis and treatment prevent nearly all complications.
💊 How Is PKU Treated?
The main treatment for PKU is a lifelong low-phenylalanine diet, which prevents toxic buildup and allows normal brain development.
✔ Strict protein-restricted diet – Avoids foods high in phenylalanine, such as meat, dairy, eggs, nuts, and soy.
✔ Special medical formula – Provides essential nutrients without excess phenylalanine.
✔ New drug therapies (e.g., Kuvan, Pegvaliase) – Help some patients process phenylalanine more efficiently.
📌 Fact: With early diagnosis and proper diet, individuals with PKU can lead healthy, normal lives.
📌 Final Thoughts
Phenylketonuria (PKU) is a serious but treatable metabolic disorder that prevents proper protein metabolism. Newborn screening plays a critical role in early detection, allowing lifelong dietary management to prevent brain damage and ensure normal development.
