Pku

Pku in D alt

Phenylketonuria (PKU) is a rare genetic disorder that increases the levels of a substance called phenylalanine in the blood. Phenylalanine is a building block of proteins (an amino acid) that is obtained through the diet. It is found in all proteins and in some artificial sweeteners. In individuals with PKU, a mutation in the gene that codes for the enzyme needed to break down phenylalanine prevents the body from processing this amino acid properly.

Causes

PKU is caused by mutations in the PAH gene that result in reduced activity of phenylalanine hydroxylase, an enzyme necessary for the metabolism of phenylalanine. Without adequate levels of this enzyme, phenylalanine accumulates in the body, leading to various health problems. PKU is inherited in an autosomal recessive pattern, meaning that an individual must inherit two copies of the mutated gene, one from each parent, to be affected.

Symptoms

The accumulation of phenylalanine in individuals with PKU can cause:

• Intellectual disability
• Developmental delays
• Behavioral, emotional, and social problems
• Seizures
• Skin rashes (eczema)
• A musty odor in the breath, skin, or urine, due to excess phenylalanine

Early diagnosis and treatment can help prevent the severe outcomes associated with PKU.

Diagnosis

PKU is most commonly diagnosed through newborn screening, a test done on infants shortly after birth to identify certain genetic or metabolic conditions that can lead to serious health problems. The test involves measuring the phenylalanine levels in the baby's blood.

Treatment

The primary treatment for PKU involves a diet low in phenylalanine. This requires strict dietary management to limit the intake of foods high in protein, such as meat, eggs, and dairy products. Special low-protein foods and phenylalanine-free medical formulas are often necessary to maintain safe phenylalanine levels.

In some cases, medication such as sapropterin (a synthetic form of the enzyme cofactor BH4) may be used in conjunction with dietary management to help reduce phenylalanine levels in the blood.

Prognosis

With early and consistent treatment, individuals with PKU can lead healthy lives. However, it is crucial for those with PKU to adhere to their dietary restrictions and treatment plan throughout their lives to prevent intellectual disability and other complications.

Epidemiology

PKU affects approximately 1 in 10,000 to 15,000 newborns in the United States. The condition is less common in African and Asian populations.