What is phenylketonuria?

What is the overall profile of phenylketonuria? For a disease like phenylketonuria, if it is not treated in time, it will cause serious consequences and may even threaten life, so it is necessary to check and treat it as soon as possible. Let's take a look at the overall profile of phenylketonuria!

Most PKU children are normal at birth, with no obvious clinical symptoms in the neonatal period. Untreated children gradually show delayed intellectual and motor development after 3 to 4 months, with their hair turning from black to yellow, their skin white, their body and urine having a special mouse odor, and often eczema. As they age, the children's intellectual disability becomes more and more obvious, and about 60% of older children have severe intellectual disabilities.

Two-thirds of the children have mild neurological signs, such as increased muscle tension, hyperreflexia, microcephaly, etc. Severe cases may have cerebral palsy. About one-quarter of the children have epileptic seizures, which often appear before 18 months old and may manifest as infantile spasms, nodding seizures or other forms. About 80% of the children have abnormal electroencephalograms, with the main abnormal manifestations being epileptic discharges, and a few have abnormal background activity. After treatment, the blood phenylalanine concentration decreases and the electroencephalogram also improves significantly.

The diagnosis of phenylketonuria in patients is based on the symptoms of mental retardation, yellow hair, white skin, motor and language development retardation, and elevated phenylalanine in blood tests. It can be diagnosed by excluding other diseases that cause elevated phenylalanine. However, in some places, doctors do not know enough about this disease. When encountering such patients, they fail to think of this disease and do not conduct relevant examinations, which often leads to missed diagnosis or misdiagnosis. Therefore, this disease needs to be taken seriously by doctors. The current newborn disease screening can diagnose PKU before the onset of the disease and provide early treatment, so PKU children are less common than before.

To prevent the onset of phenylketonuria, early diagnosis and early treatment are necessary to avoid damage to the nervous system caused by excessive phenylalanine metabolites, such as phenylpyruvate, phenylacetate and phenyllactic acid. Since it takes a certain amount of time for phenylpyruvate, phenylacetate and phenyllactic acid in the body to accumulate to the concentration required to damage the brain, even in PKU children, the concentration of these abnormal metabolites often only increases within 1 to 2 months after birth, which does not cause irreversible damage.