目的　探讨深圳地区苯丙酮尿症 (PKU)患者血苯丙氨酸羟化酶 (phenylalaninehydroxylase ,PAH)基因单核苷酸多态性位点。方法　设计 7对引物 ,应用多聚酶链反应 -单链构像多态 (PCR -SSCP)银染技术和DNA序列分析了 3个PKU家族共 13个成员的PAH基因。结果　PCR -SSCP分析发现 ,其中 2个家族的子女及其父母有电泳条带异常 ,测序结果示两多态性位点均在内含子 10上。结论　 2种突变类型可能为单核苷酸变化 Objective To investigate the single nucleotide polymorphism (SNP) of phenylalanine hydroxylase (PAH) in patients with phenylketonuria (PKU) in Shenzhen. Methods Seven pairs of primers were designed and the PAH genes of 13 members of 3 PKU families were analyzed by PCR-SSCP and DNA sequencing. Results PCR-SSCP analysis showed that electrophoresis bands were abnormal in children and parents of the two families. The sequencing results showed that both polymorphic loci were in intron 10. Conclusion The two types of mutations may be single nucleotide changes