Abstract: Objective  To determine the mutation spectrum of the PAH gene in PKU children in Ningxia, six exons of PAH gene were sequenced in each of the 30 phenylketonuria (PKU) children. Methods 30 children diagnosed as PKU by the neonatal  sereening and/or GC/MS analysis in Ningxia were enrolled in this study. Meanwhile, 30 normal children were served as controls.  The exons 3、 5、 6、 7、11 and 12 of the PAH gene were amplified by polymerase chain reaction. The amplicons were analyzed by  single strand conformation polymorphism and sequencing. Results Mutations were identified for 51 of 60 alleles in this study,  representing a mutation detection rate of 85%. A total of 16 different causative mutations were detected, including 8 missense  mutations (R241C、R243Q、R252Q、G257V、R359K、R408Q、R413P、Q419R), 3 splicing mutations (IVS4-1G?>? A、 Y204C、IVS7+2T?>?A), 3 nonsense mutations (R111X、Q160X、Y356X), 1 synonymous mutation (V399V) and 1 deletion  (N183del). R243Q (18.3%) had the highest frequency of PAH mutations, and then Y204C (11.7%)、IVS4-1G?>? A (10.0%)、 R111X (6.7%) and IVS7+2T?>? A (6.7%). For the first time in China, two novel mutations, deletion mutation N183del  （C.547549delGAA）  in exon 6 and missense mutation R359K (C.1078G?>?A) in exon11, were identified in PKU children. Two silent  mutations, V245V (C.735G?>?A) and Q232Q (C.696A?>?G), were observed in PKU children and the controls, but there were no  significant difference between them (P?>?0.05). Conclusions The most common mutations were missense and R243Q had the  highest frequency of mutation. The identification of 2 novel mutations expands the spectrum of Chinese PAH mutations.