RESEARCH ON EXON 7 OF HUMAN PHENYLALANINE HYDROXYLASE GENE IN TIANJIN AREA

Song Li, Meng Ying-tao, Gao Wen-ying, Xu Feng-duo, Shan Zhong-min

Pediatric Research Institute, Tianjin Children’s Hospital, Tianjin, China

Objective: To investigate the characteristic of exon 7 on phenylalanine hydroxylase gene in Tianjin area.

Method: The DNA samples of 41 PKU patients were analyzed by polymerase chain reaction-single strand conformation polymorphism (PCR-SSCP) and direct sequencing of PCR products.

Results: Totally six DNA-bands were showed in SSCP electrophoretogram and four kinds of mutations were identified by direct sequence. The mutations were R243Q and G257V missense mutations, R261X nonsense mutation and V245V silent mutation. Their frequencies were 14.6%(12/82), 1.2%(1/82), 1.2%(1/82) and 78%(64 /82) respectively. The R261X nonsense mutation has not been reported before in China.

Conclusion: The R243Q mutation frequency (14.6%) in this report was higher than Shanghai (9.5%) reported by Zhang M(1995) and lower than Beijing(23.3%) reported by Song F(1995). The mutation G257V was the second time found in the population of North China. The R261X nonsense mutation has not been reported in China before. 78% frequency of the silent mutation V245V in this report was much higher than the PKU population either in Shanghai or in Northeastern China, which were 6% and 37.8% respectively. In generally, it has own features of PAH gene mutation in Tianjin area.

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