Polymorphism and Sequencing Analysis of Mutations in Patients with Phenylketonuria

In a study aiming at understanding the characteristics of mutations in exon 6 and exon 7 of the PAH gene in PKU patients, mutations in exon 6 and exon 7 and the flanking intronic sequence of the phenylalanine hydroxylase (PAH) gene were detected by polymerase chain reaction (PCR)/single-strand conformation polymorphism (SSCP) analysis and direct DNA sequencing in 35 phenylketonuria (PKU) patients in the Jilin area. In these experiments, nine different mutations were identified in 70 alleles (31/70, 44.2%). R243Q (25.7%) and EX6-96A>G (5.7%) were found to be the most prevalent mutations followed by IVS7 + 2T > A (2.9%), R241C (2.9%), L242F (1.4%), G247R (1.4%), G247V (1.4%), R261X (1.4%) and R176X (1.4%). Two polymorphism sites, Q232Q (94.3%) and V245V (67.1%), were detected in the study. It is speculated that the ethnic diversity and area diversity exist in the PAH cDNA sequence. The mutation types of the PAH gene in Jilin area were found to be similar to those in other areas of China, with almost the same mutation frequency at high-frequency mutation sites and different mutation frequencies at other mutation sites.