The significance of the phenylalanine hydroxylase gene mutation in the diagnosis of phenylketonuria

ObjectiveTo explore the diagnostic significance of phenylalanine hydroxylase(PAH) gene mmutation in phenylketonuria(PKU), and its influence on children with PKU.

MethodsOne hundred and thirty-five children with PKU were investigated.The mutations of PAH gene in all cases were detected using polymerase chain reaction and Sanger sequencing.The large number of deletion and duplication of PAH gene were investigated using multiplex ligation-dependent probe amplification(MLPA), and the data of detection was treated with SPSS 21.0 software to analyze the mutation of PAH and its effects on intelligence quotient of KPU children.

ResultsAmong the 135 PKU children(270 pairs of PAH alleles), the PAH gene mutations in 12 children(accounted for 8.89%) were found, and 12 mutation sites were identified, the mutation frequency of R243Q, Y204C, R241C, IVS4-1, R413P, R111X, R261Q, W326X and Y356X were 5.19%, 5.19%, 3.70%, 2.96%, 2.22%, 1.48%, 1.48%, 0.74% and 0.74% of the total PAH alleles, respectively, while the mutation frequency of E56D, F161S and A345T was not obvious.The results of PAH gene mutations detected by SNaPShot, Sanger and MLPA in 12 children with PKU showed that the homozygous mutations accounted for 16.67%, and the compound and heterozygous mutations accounted for 83.33%.The PA and FIQ scores in 12 children with PKU after intervention were lower and higher than those before intervention, respectively(P < 0.05), and the differences of the VIQ and PIQ between before and after intervention were not statistically significant(P>0.05).The results of Pearson analysis showed that the mean controlled concentration of PAH in 12 PAH-mutated PKU children during treatment was negatively correlated with the intelligence quotient test value at the first year of life(r=-0.924, P < 0.01).

ConclusionsIn the process of clinical treatment of PKU children, the scientific and reasonable detection of PAH gene mutation and strict control of children's PAH blood concentration have better clinical application and promotion value, and it is also one of the key factors to improve children's intelligence quotient.