OBJECTIVETo investigate the feature of phenylalanine hydroxylase (PAH) gene mutations and provide guidance for genetic and prenatal diagnosis of patients with phenylketonuria from Shaanxi.

METHODSFor 55 patients whose blood Phe concentration was over 2.0 mg/dL, potential mutations in 13 exons and flanking sequences of the PAH gene were detected by PCR and DNA sequencing.

RESULTSA total of 98 mutations were detected in 110 PAH alleles, with the detection rate being 89.10%. Nine mutations have been identified in exon 7, which accounted for 33.67% of all. Exon 12 (14.29%) and exon 3 (12.24%) have followed. Thirty eight mutations, locating in exon2-exon12 and the flanking sequence, were detected in the 55 PKU patients. p.R243Q (24.49%) was the commonest mutation, whilstp.A47E, p.I65S and p.A259T were first discovered in China. After querying international databases including PAHdb and HGMD, the p.C334X was verified as the novel PAH gene mutation.

CONCLUSIONThe mutation spectrum of the PAH gene in Shaanxi has been identified. And a novel mutation has been identified. This may facilitate the diagnosis of PKU in the future.