Gene mutations in 32 family with phenylketonuria

Abstract

Objective By detecting the mutations spectrum of phenylalanine hydroxylase(PAH) gene in phe-nylketonuria(PKU) patients and their parents.The researchers analyzed the gene mutation features and high-frequency mutations and determined the relationship between the genotype and the phenotype, which would provide a theoretical basis for the early diagnosis and genetic consultation of PKU children in the region. Methods In this study, 13 exons and their flanking introns of the PAH gene in 32 PKU patients and their parents from Wuxi and Suqian in Jiangsu province were sequenced by using the next-generation sequencing(NGS) technology. Results Sixty-one mutant sites and 32 mutant genes were detected in 32 PKU patients, and the mutation detection rate was 95.31%(61/64 cases). The variants at c. 721C>T, c.1068C>A, c.611A>G, c.1197A>T, c.728G>A, c.331C>T and c. 442-1G>A were common mutations in the region with mutation frequency over 5%.What's more, 4 novel variants of c. 699C>G, c.265C>T, c.722G>A and c. 1194A>G were found.Of those, c.699C>G was not recorded in the PAH variant database and HGMD database and.c.265C>T, c.722G>A, and c. 1194A>G were first reported in the Chinese population.Genotype-accurate biochemical phenotype correlation by using the Guldberg AV system revealed consistency rate of 38.0%(8/21 cases), which the consistency rate between accurate biochemical phenotype and predictive phenotype of moderate to severe genotype was 92.3%(12/13 cases), and mild genotype was 50.0% (4/8 cases). Conclusions The PAH gene variants of PKU patients in Jiangsu province are distributed mainly in exons 7, of which the highest frequency gene mutation is c. 721 c>T.Moreover, one novel variant c. 699C>G was reported for the first time.The PKU children inherit the PAH mutation gene mainly from both parents.There are definite correlation between the genotypes and phenotypes. Key words: Phenylketonuria; Phenylalanine hydroxylase; Mutations