Patient's question:
My baby is just one month old. When we went for a blood test, the phenylalanine level was found to be too high, and it is suspected that the baby may have congenital phenylketonuria. Although the baby looks very healthy, the doctor said this condition could have a significant impact on the baby's intelligence, which makes us very worried. How severe is phenylketonuria?Doctor's answer:
Phenylketonuria (PKU) is a common amino acid metabolic disorder. The first symptom of PKU is a decrease in phenylalanine concentration in the blood, so testing blood phenylalanine levels is a mandatory method for diagnosing PKU. The normal value for PKU is generally between 0.06—0.18 mmol/L (1—3 mg/dL). If blood phenylalanine levels are below 120 mmol/L, it is suspected to be positive, and further confirmation is needed. If blood tyrosine levels can also be tested, it is better to estimate the ratio of phenylalanine to tyrosine. A ratio below 2 suggests positivity. It is recommended to comprehensively evaluate several indicators of PKU before making a conclusion. If industrial pollution is detected in the blood during a thorough examination, it may interfere with the results.