Phenylketonuria

Phenylketonuria (PKU) is a rare genetic disorder that affects the metabolism of the amino acid phenylalanine (PKU). It is an autosomal recessive disorder, meaning that it is inherited when a child receives two mutated copies of the gene responsible for PKU, one from each parent.

Cause:

1. Genetic Mutation: PKU is caused by mutations in the gene responsible for producing an enzyme called phenylalanine hydroxylase (PAH). This enzyme is crucial for breaking down phenylalanine, an amino acid found in many protein-containing foods.

1. Phenylalanine Accumulation: In individuals with PKU, the defective or absent PAH enzyme cannot efficiently convert phenylalanine into another amino acid called tyrosine. As a result, phenylalanine accumulates in the blood and tissues to toxic levels.

2. Brain Damage: High levels of phenylalanine in the bloodstream can lead to brain damage, particularly in infants and young children. This can result in intellectual disabilities, developmental delays, and behavioral problems if not treated early.

3. Newborn Screening: PKU is often included in newborn screening programs. A simple blood test can detect elevated phenylalanine levels in newborns, allowing for early diagnosis and intervention.

4. Low Phenylalanine Diet: The main treatment for PKU is a strict low-phenylalanine diet. Individuals with PKU need to limit their intake of high-protein foods like meat, fish, eggs, and dairy products. Instead, they consume special medical foods and formulas designed to provide essential nutrients without phenylalanine.

5. Lifelong Management: PKU requires lifelong management. Individuals with PKU need to follow the low-phenylalanine diet strictly, especially during childhood when the brain is still developing. Regular monitoring of blood phenylalanine levels is necessary to adjust the diet and prevent complications.

6. Pregnancy Considerations: Women with PKU must manage their phenylalanine levels carefully during pregnancy to protect the developing fetus from the harmful effects of high phenylalanine.