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目的:对2例短肋多指综合征3型（short rib polydactyly syndrome type Ⅲ，SRPSⅢ）的胎儿进行产前诊断，明确其发病的分子遗传学病因。方法:应用二代测序技术（next generation sequencing，NGS）对2015年8月和2020年6月于郑州大学第一附属医院就诊的2个患病胎儿（先证者）进行遗传性骨病226个相关致病基因检测。发现可疑致病位点后，对家系成员进行Sanger双向测序验证分析。确定致病变异后，对家系1的高危胎儿进行产前诊断。结果:2个SRPS Ⅲ家系均发现了n DYNC2H1基因变异，其中家系1先证者携带n DYNC2H1基因c.5881A>G（p.Lys1961Glu）纯合变异，父母分别为携带者；家系2先证者n DYNC2H1基因存在c.10606C>T（p.Arg3536*）和c.8954T>G（p.Val2985Gly）复合杂合变异，分别来自父亲和母亲。2个家系均符合常染色体隐性遗传，n DYNC2H1基因c.5881A>G（p.Lys1961Glu）、c.8954T>G（p.Val2985Gly）为首次报道的疑似致病性变异。产前诊断结果显示家系1胎儿（Ⅱ-7）未见n DYNC2H1基因c.5881A>G（p.Lys1961Glu）变异，孕妇选择继续妊娠，分娩后取脐带血行基因检测，结果与产前基因诊断结果一致。n 结论:DYNC2H1基因变异是这2个家系的致病原因。n “,”Objective:To investigate the molecular genetic etiology of two fetuses with short rib-polydactyly syndrome type Ⅲ (SRPS Ⅲ).Methods:Next-generation sequencing (NGS) was used to detect 226 known genes related to inherited skeletal dysplasia in two fetuses with SRPS Ⅲ diagnosed in the First Affiliated Hospital of Zhengzhou University in August 2015 and June 2020. Suspect pathological variants were verified in the pedigree members using Sanger sequencing. The prenatal genetic diagnosis of the high-risk fetus in pedigree one was conducted to identify the confirmed pathogenic variation.Results:The homozygous mutation of n DYNC2H1 gene c.5881A>G(p.Lys1961Glu) was identified in the proband in pedigree one, and the parents were the carriers. The proband in pedigree two carried compound heterozygous mutations in then DYNC2H1 gene with c.10606C>T(p.Arg3536*) inherited from the father and c.8954T>G(p.Val2985Gly) from the mother. Autosomal recessive inheritance was confirmed in both pedigrees. Mutations of c.5881A>G(p.Lys1961Glu) and c.8954T>G(p.Val2985Gly) in then DYNC2H1 gene were likely pathogenic variants and had not been reported before. The prenatal diagnosis did not identify the n DYNC2H1 gene c.5881A>G(p.Lys1961Glu) mutation in the fetus (Ⅱ-7) in pedigree one, which was confirmed by the umbilical cord blood sample after birth.n Conclusion:DYNC2H1 gene mutation underlies the fetal skeletal dysplasia in the two pedigrees.n