What are the common symptoms of phenylketonuria?

The "killer" of baby intelligence - neonatal phenylketonuria is a hereditary disease. Due to the lack of phenylalanine hydroxylase in the body, the human body cannot metabolize phenylalanine. In this way, phenylalanine will accumulate in the body, causing damage to human organs, especially the brain, and seriously affecting the child's intelligence. So, what are the common manifestations of phenylketonuria?

Overview

Phenylketonuria, also known as PKU, is a rare genetic disorder that causes an amino acid called phenylalanine to build up in the body. PKU is caused by a defect in a gene that helps produce the enzyme needed to break down phenylalanine.

Without the enzyme needed to process phenylalanine, PKU patients can experience a dangerous buildup when they eat foods containing protein or consume the artificial sweetener aspartame. This can eventually lead to serious health problems.

For the rest of their lives, people with PKU—infants, children, and adults—need to follow a diet that restricts phenylalanine, an amino acid found primarily in foods containing protein.

Babies in the United States and many other countries are screened for PKU soon after birth. Recognizing PKU right away can help prevent major health problems.

symptom

Newborns with PKU initially have no symptoms. However, without treatment, infants usually develop symptoms of PKU within a few months.

Signs and symptoms of PKU can range from mild to severe and may include:

A musty odor on your breath, skin, or urine caused by too much phenylalanine in your body.

Neurological disorders, which may include epilepsy

Skin rash (eczema)

White skin and blue eyes because phenylalanine cannot be converted into melanin - the pigment responsible for hair and skin color.

An abnormally small head (microcephaly)

Hyperactivity

Intellectual Disability

Delayed development

Behavioral, emotional, and social problems

Mental disorders

Different severity

The severity of PKU depends on the type.

Classic PKU. The most severe form of this disease is called classic PKU. The enzyme needed to convert phenylalanine is missing or severely reduced, resulting in high levels of phenylalanine and severe brain damage.

Less severe PKU. In mild or moderate forms, the enzyme retains some function, so phenylalanine levels are not as high, leading to less risk of severe brain damage.

But most children with the disease still need a special PKU diet to prevent intellectual disability and other complications.

Pregnancy and PKU

Women who have PKU and become pregnant face another condition, called maternal PKU. If a woman does not follow a special PKU diet before and during pregnancy, blood phenylalanine levels can rise, harming the developing fetus or causing miscarriage.

Even women with milder forms of PKU may put their unborn children at risk by not following the PKU diet.

Babies born to mothers with high phenylalanine levels do not usually inherit PKU. However, if a pregnant woman has high levels of phenylalanine in her blood, serious consequences can occur. Complications at birth may include:

Low birth weight

Delayed development

Facial abnormalities

Abnormally small head

Heart defects and other heart problems

Intellectual Disability

Behavioral problems

Neonatal phenylketonuria is a common chromosomal recessive genetic disease. It is mainly caused by genetic abnormalities that lead to the lack of a specific enzyme in the child's body, which makes it impossible to metabolize phenylalanine normally, causing phenylalanine and other metabolites to accumulate in the body, thereby causing a series of clinical manifestations such as mental retardation.

First, children with neonatal phenylketonuria tend to have pale skin and often have symptoms of eczema. Due to the reduced synthesis of melanin, the children's hair is light, dry, and colorless.

Second, the child's head circumference is relatively small and the deciduous teeth grow slowly.

Third, the children's sweat and urine have unpleasant odors of rat urine and mold.

Fourth, some children also show symptoms such as irritability and irritability in the early stage. Some children may have feeding difficulties, vomiting, restless sleep, and easy crying.

Fifth, the symptoms of intellectual disability generally begin to become apparent 4 to 9 months after birth, especially language development disorders. Some children also suffer from epileptic seizures.

Neonatal phenylketonuria patients begin to show symptoms 3 to 6 months after birth. If parents can detect it early, treat it in time, and use low-phenylalanine milk powder instead of regular infant milk powder or breast milk, they can avoid the accumulation of phenylalanine in the body and prevent brain damage.