Patient's question:
When my child was 7 days old, the doctor drew blood for screening. At 22 days, I was told there were doubts of phenylketonuria. What is the normal value for phenylketonuria? How is 2.0 considered normal? I am very anxious and hope it's just a false alarm. The help I need: Is 2.0 normal for phenylketonuria?Doctor's answer:
Normal phenylalanine concentration is 0.06—0.18 mmol/L (1—3 mg/dL). In newborns, there are no obvious special clinical diagnostic symptoms. It may take 3 to 4 months for symptoms such as intellectual and motor developmental delays, hair color changing from black to yellow, pale skin, and a special mouse-like odor in the body and urine to appear. Phenylketonuria is a congenital inherited metabolic disease caused by a deficiency in the enzyme of the phenylalanine (PA) catabolic pathway, which prevents phenylalanine from being converted into tyrosine. This leads to the accumulation of phenylalanine and its ketones, and a large amount of them are excreted in the urine.