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目的:研究游离DNA单分子标签检测（cell-free DNA barcode-enabled single-molecule test, cfBEST）技术用于苯丙酮尿症（phenylketonuria, PKU）无创产前诊断的适用性和可行性。方法:研究对象为2019年7月至9月郑州大学第一附属医院进行产前诊断的4例诊断为n PAH基因热点突变的苯丙酮尿症家系。采用cfBEST技术进行检测，设计巢式聚合酶链反应引物，计算孕妇血浆游离DNA突变频率和胎儿基因型，并将cfBEST技术的检测结果与介入性产前诊断结果比较。对数据采用描述性统计分析。n 结果:cfBEST技术检测发现，家系1中c.603T>G和c.842+2T>A位点的突变频率为48.40%（291/601）和9.70%（61/628），胎儿2个位点均为杂合突变型，为PKU患者。家系2中c.1238G>C和c.842+2T>A的突变频率分别为43.70%（786/1 798）和0%（0/1 550），胎儿2个位点均为野生型，非PKU患者，亦非携带者。家系3中，c.1045T>G和c.728G>A的突变频率分别为44.00%（930/2 112）和0%（0/705），胎儿2个位点均为野生型，非PKU患者，亦非携带者。家系4中，c.755G>A和c.728G>A的突变频率分别为45.40%（743/1 637）和4.50%（28/849），胎儿位点分别为野生型和杂合突变型，为携带者。介入性产前诊断结果与cfBEST技术检测结果完全一致。家系1选择引产，其余3个家系选择继续妊娠至足月分娩，其新生儿筛查苯丙氨酸水平均G and c.842+2T>A mutations in maternal plasma cell-free DNA were 48.40% (291/601) and 9.70% (61/628), which was detected by cfBEST. The fetus was diagnosed with phenylketonuria with two heterozygous mutations. In pedigree 2, the frequency of c.1238G>C and c.842+2T>A mutations in maternal plasma cell-free DNA was 43.70% (786/1 798) and 0% (0/1 550), respectively. Both mutations were wild-type, and the fetus was neither phenylketonuria nor a carrier. In pedigree 3, the frequency of c.1045T>G and c.728G>A mutations in maternal plasma cell-free DNA was 44.00% (930/2 112) and 0% (0/705), respectively, suggesting that both mutations in the fetus were wild-type, and the fetus was neither phenylketonuria nor a carrier. In pedigree 4, the frequency of c.755G>A and c.728G>A mutations were 45.40% (743/1 637) and 4.50% (28/849), respectively, which indicated that the former was wild-type, and the latter was heterozygous; namely the fetus was a carrier of phenylketonuria. The results of cfBEST were consistent with those of invasive prenatal diagnosis. Three pedigrees (Pedigree 2, 3 and 4) continued the pregnancy to full-term, and the phenylalanine levels in the neonates were all below 120 μmol/L. No abnormalities were reported in those three infants during follow-ups at one, three, and six months after birth.Conclusions:The cfBEST could be used for non-invasive prenatal diagnosis of phenylketonuria caused by n PAH gene mutation, but further studies with a larger sample size are needed.n