Background Phenylketonuria (PKU) is one of the most common inherited inborn errors of metabolism caused by the deficiency of phenylalanine hydroxylase (PAH), and then impairs postnatal cognitive development. The incidence of various PAH variations differs by race and ethnicity.
Objective To investigate the characteristics of PAH gene mutations in children with PKU in Jilin and Liaoning province.
Methods From 2016 to 2018 , 80 PKU patients and their families were recruited for this study in the hospitals of Jilin and Liaoning province. Patients were sequentially screened for single-base variants within PAH via direct Sanger sequencing, and 13 exons of PAH gene and their flanking sequences (5’ and 3’ non-coding regions) were included by the sequencing.
Results Of the 292 mutant alleles, 161 mutations were detected in all patients, with the detection rate of 55.14%. In addition, R243Q was the most prevalent mutation (the frequency was 15.75%) in terms of mutation frequency. Other mutations with relatively high frequencies were IVS11-3 A＞T, R413P, IVS4-1 G＞A and EX6-96A＞G (4.11%, 3.42%, 3.08%, 3.08%, respectively). Five mutations, including Y356*, R111*, R241C, R53H and IVS2 + 19 T＞C were found with relatively lower frequencies (ranging from 1% to 3%). We also found the novel F294S mutation in exon 8.
Conclusion This study shows the results of mutations in the PAH gene of the 80 children with PKU in Jilin and Liaoning province, which may provide references for reducing the incidence of PKU in these provinces.
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