Patient's question:
A newborn baby discovered phenylketonuria at 14 days and is currently not being treated.Doctor's answer:
Hello! Phenylketonuria (PKU) is caused by abnormal phenylalanine metabolism in the body. Phenylalanine is an essential amino acid required for human growth and metabolism, and the activity of phenylalanine hydroxylase requires tetrahydrobiopterin as a cofactor to achieve better effects. A decrease in phenylalanine hydroxylase activity or a deficiency in tetrahydrobiopterin can prevent phenylalanine from being converted into tyrosine, leading to a significant increase in phenylalanine and its byproduct metabolites—phenylpyruvate, phenylacetic acid, and phenyllactic acid—which can cause brain damage and result in the onset of the disease. If PKU in children is not treated or treatment is delayed, most children will experience delays in intellectual, motor, and language development. However, if diagnosis and treatment are initiated before symptoms appear, such as in newborn screening-detected PKU cases, timely treatment can allow nearly 90% of children to achieve normal intelligence. Only a small portion of children may still experience intellectual decline due to poor treatment compliance or severe conditions, resulting in poor control of blood phenylalanine levels.Advice: Hello! The treatment for PKU requires targeted measures based on its classification. You must first determine the classification and then use medication accordingly. Generally, the target range for blood phenylalanine levels is as follows:
- 0–3 years: 120–240 mmol/L
- 3–8 years: 180–360 mmol/L
- 8–13 years: 180–480 mmol/L
- 13–18 years: 180–600 mmol/L
- >18 years: 180–900 mmol/L
This condition is a genetic metabolic disorder and cannot be completely cured. For families with children already diagnosed with PKU, if the parents wish to have another child, prenatal diagnosis can be used to determine whether the fetus has PKU.