The spectrum of phenylalanine hydroxylase variants and genotype–phenotype correlation in phenylketonuria patients in Gansu, China

Background: Phenylketonuria (PKU) is a common, congenital, autosomal recessive, metabolic disorder caused by Phenylalanine hydroxylase (PAH) variants. Methods: 967 PKU patients from Gansu, China were genotyped by Sanger sequencing, multiplex ligation-dependent probe amplification, and whole exome sequencing. We analyzed the variants of PAH exons, their flanking sequences, and introns. Results: The detection of deep intronic variants in PAH gene can significantly improve the genetic diagnostic rate of PKU. The distribution of PAH variants among PKU subtypes may be related to the unique genetic background in Gansu, China. Conclusion: The identification of PAH hotspot variants will aid the development of large-scale neonatal genetic screening for PKU. The five new PAH variants found in this study further expand the spectrum of PAH variants. Genotype–phenotype correlation analysis may help predict the prognosis of PKU patients and enable precise treatment regimens to be developed.