Which are the symptoms of Phenylketonuria?

Symptoms of Phenylketonuria (PKU)

Phenylketonuria (PKU) is a rare genetic disorder that affects the body's ability to break down an amino acid called phenylalanine. This condition is caused by a deficiency of an enzyme called phenylalanine hydroxylase, which is responsible for converting phenylalanine into another amino acid called tyrosine. Without this enzyme, phenylalanine builds up in the blood and can cause various symptoms and complications.

Early Symptoms

PKU is typically diagnosed shortly after birth through newborn screening tests. However, in some cases, symptoms may appear before the screening or go unnoticed until later in infancy. The early signs and symptoms of PKU may include:

• Musty odor: Infants with PKU may have a distinct musty or mousy odor due to the accumulation of phenylalanine in their sweat and urine.


• Developmental delays: Children with PKU may exhibit delays in reaching developmental milestones, such as sitting, crawling, and walking.


• Intellectual disability: If left untreated, PKU can lead to intellectual disability. Children may have learning difficulties, impaired cognitive function, and lower IQ scores.


• Behavioral problems: Some individuals with PKU may experience behavioral issues, including hyperactivity, attention deficit disorder, and emotional instability.


• Seizures: In severe cases of PKU, seizures may occur.

Dietary Management and Late Symptoms

PKU is a lifelong condition, but with early diagnosis and proper management, individuals with PKU can lead healthy lives. The most crucial aspect of managing PKU is following a strict low-phenylalanine diet. This diet involves avoiding foods high in phenylalanine, such as meat, fish, eggs, dairy products, nuts, and certain grains. Instead, individuals with PKU consume specially formulated medical foods and low-protein alternatives.

When individuals with PKU do not adhere to the prescribed diet or fail to manage their condition effectively, they may experience late symptoms and complications, including:

• Intellectual and cognitive decline: Without proper treatment, the accumulation of phenylalanine can lead to a decline in intellectual abilities and cognitive function over time.


• Psychiatric disorders: Some individuals with PKU may develop psychiatric disorders, such as depression, anxiety, and psychosis.


• Neurological problems: PKU can cause neurological issues, including tremors, abnormal movements, and difficulties with coordination and balance.


• Skin disorders: Skin conditions like eczema and rashes may occur in individuals with untreated PKU.


• Microcephaly: In severe cases, PKU can lead to microcephaly, a condition characterized by an abnormally small head size and potential brain abnormalities.


• Cardiovascular issues: Some studies suggest that individuals with PKU may have an increased risk of cardiovascular problems, such as high blood pressure and heart disease.

It is important to note that the severity and presentation of symptoms can vary among individuals with PKU. Some individuals may have milder forms of the condition and experience fewer symptoms, while others may have more severe symptoms and complications.

Conclusion

Phenylketonuria (PKU) is a genetic disorder that affects the body's ability to process phenylalanine. Early diagnosis through newborn screening and strict dietary management are crucial for individuals with PKU. By following a low-phenylalanine diet and receiving appropriate medical care, individuals with PKU can minimize symptoms, prevent complications, and lead fulfilling lives.