Characterization of phenylalanine hydroxylase gene mutations in phenylketonuria in Xinjiang of China

To investigate the spectrum and frequency of phenylalanine hydroxylase (PAH) gene mutations in phenylketonuria (PKU) patients in Xinjiang, China. Polymerase chain reaction (PCR), in combination with single-strand conformation polymorphism (SSCP) and DNA sequencing analyses were performed, to screen potential mutations in the PAH gene in 46 individual PKU patients. Direct DNA sequencing was used to analyze the all of the exons in the PAH gene, including the promoter and flanking intron regions, in another 15 PKU patients. Our results indicated that, 30 different mutation types were identified in all 122 PAH alleles, with the mutation detection rate of 78.7% (96/122). Four novel mutations, i.e., 5'-Flanking -626G>A, 5'-Flanking -480DelACT, S196fsX4, and IVS8+1G>C, were identified for the first time. Similar to other regions in North China, R243Q, EX6-96A>G, IVS4-1A>G, R111X, and Y356X were the most prevalent PAH mutations in PKU patients from Xinjiang. Additionally, common mutations showed different frequencies in Xinjiang, when compared to other areas. Furthermore, sixteen different PAH gene mutation types were identified for the first time in the minorities in Xinjiang. Distinctive mutation spectrum of PAH gene in PKU patients from Xinjiang were characterized, which may promote the construction of PAH gene mutation database and serve as valuable tools for genetic diagnosis and counseling, and prognostic evaluation for PKU cases in the local area.