目的 对甘肃地区苯丙酮尿症（phenylketonuria, PKU）患儿进行分子流行病学调查，以期为PKU的干预策略提供基础性数据。 方法 回顾性收集2012年1月—2024年12月甘肃省妇幼保健院就诊的1 159个PKU患儿家系，通过Sanger测序、多重连接依赖探针扩增技术、全外显子组测序以及深部内含子变异分析对PAH基因进行分析。 结果 1 159例PKU患儿中，患儿的2 318个等位基因中检测到2 295个变异，检出率为99.01%。其中457个经典型PKU患儿家系检出率为100%（914/914），456个轻度PKU患儿家系检出率为99.45%（907/912），246个轻度高苯丙氨酸血症患儿家系检出率为96.34%（474/492）。检测到的2 295个等位基因变异分属于208种变异，其中出现频率最高的是c.728G>A（14.95%，343/2 295），其次为c.611A>G（4.88%，112/2 295），随后为c.721C>T（4.79%，110/2 295）。前23位热点变异的累计频率达70.28%（1 613/2 295）。外显子7上检测到的变异等位最多（29.19%，670/2 295）。 结论 对PAH基因进行深部内含子变异分析，可以进一步提高PKU基因诊断率。针对PAH基因热点变异位点与区域设计研发相应检测试剂盒可能有助于PKU的精准筛查与防控。

Objective To investigate the molecular epidemiology of children with phenylketonuria (PKU) in Gansu, China, providing foundational data for intervention strategies. Methods A retrospective analysis was conducted on 1 159 PKU families who attended Gansu Provincial Maternity and Child Care Hospital from January 2012 to December 2024. Sanger sequencing, multiplex ligation-dependent probe amplification, whole exome sequencing, and deep intronic variant analysis were used to analyze the PAH gene. Results For the 1 159 children with PKU, 2 295 variants were identified in 2 318 alleles, resulting in a detection rate of 99.01%. The detection rates were 100% (914/914) in 457 classic PKU families, 99.45% (907/912) in 456 mild PKU families, and 96.34% (474/492) in 246 mild hyperphenylalaninemia families. The 2 295 variants detected comprised 208 distinct mutation types, among which c.728G>A (14.95%, 343/2 295) had the highest frequency, followed by c.611A>G (4.88%, 112/2 295) and c.721C>T (4.79%, 110/2 295). The cumulative frequency of the top 23 hotspot variants reached 70.28% (1 613/2 295), and most variant alleles were detected in exon 7 (29.19%, 670/2 295). Conclusions Deep intronic variant analysis of the PAH gene can improve the genetic diagnostic rate of PKU. The development of targeted detection kits for PAH hotspot variants may enable precision screening programs and enhance preventive strategies for PKU.