目的对4个6-丙酮酰-四氢蝶呤合成酶(PTPS)缺陷所致非经典型苯酮尿症家系第二胎胎儿进行产前DNA突变分析以确诊其是否受累。方法采集家系成员外周血标本及受检孕妇羊水标本,常规提取基因组DNA,以DNA测序方法进行基因突变分析,并对基因一侧的微卫星多态标记进行分析。结果 3个家系先证者为双重杂合子,一个家系先证者为纯合子,均分别来自父方和母方,待测胎儿有3例不含这两种突变,1例为杂合子。结论对PTPS基因而言,此4家系的第二胎为完全正常。 Objective To investigate the prenatal DNA mutation analysis of the second fetus of pedigree with non-classical phenylketonuria caused by four defects of pyruvate-tetrahydronopterin synthase (PTPS) to confirm whether it is involved or not. Methods The peripheral blood samples from family members and amniotic fluid samples from pregnant women were collected. The genomic DNA was routinely extracted. The gene mutation was analyzed by DNA sequencing and the microsatellite polymorphism markers on the gene side were analyzed. Results The probands of three pedigrees were double heterozygotes. One pedigree was a homozygote. All of them were from the father and the mother. Three fetuses did not contain these two mutations and one was heterozygous. Conclusion For the PTPS gene, the second line of these four lines is completely normal.