RESUMO
OBJECTIVE: To identify the pathogenic mutations of phenylalanine hydroxylase gene (PAH) in patients with phenylketonuria (PKU) from Hebei Province. METHODS: Genomic DNA was extracted from 55 unrelated PKU patients from September 2007 to July 2009. All PAH exons and exon-intron junctions were amplified by polymerase chain reaction (PCR) and sequenced. Multiplex ligation-dependent probe amplifications (MLPA) was performed to detect the deletions or duplications of PAH. Gap-PCR was used to determine the breakpoints of large deletions. RESULTS: Among them, 108 mutant alleles (98.2%) were found. All PAH exons with the exceptions of exons 9 and 13 were affected. A total of 41 different mutations were detected, including missense (n = 24), nonsense (n = 7), splicing (n = 7), small deletion (n = 1) and large deletion (n = 2). Among them, 4 missense mutations (p.Pro147Leu, p.Gly289Arg, p.Phe392Ser, p.Ile421Thr) and 2 large deletions (-4163_-406del and -1932_+3402del) were novel. The most common mutations were p.Arg243Gln (12.7%), c.611A > G (11.8%) and c.1197A > T (9.1%). CONCLUSION: The mutations of PKU patients with from Hebei Province are scattered throughout the PAH gene. Most of them are of single nucleotide substitutions, but large deletions are not rare.
