Question
The child grows slowly and has an intelligence level higher than that of their peers. Detailed examination often suggests phenylketonuria. I want to know what phenylketonuria is all about?
Answer
Phenylketonuria is a congenital amino acid metabolism disorder caused by a deficiency in the enzyme involved in the metabolism of phenylalanine, which prevents phenylalanine from being converted into tyrosine. This leads to the accumulation of phenylalanine and its keto acids, which are then excreted in large amounts in the urine. This condition is relatively common among hereditary amino acid metabolism defects and follows an autosomal recessive inheritance pattern. Parents with a family history of the disease can undergo prenatal diagnosis through DNA testing or amniotic fluid analysis for alpha-fetoprotein. Once diagnosed, increasing phenylalanine intake and early and appropriate dietary restriction can allow the child to grow up healthy and strong like any normal child. This is because the lack of phenylalanine hydroxylase in their bodies can lead to the accumulation of phenylpyruvate, so the earlier dietary restriction is implemented, the better it is for the child’s development.