小于胎龄且不伴结构异常胎儿染色体异常的研究

Genomic anomalies in small for gestational age fetuses with no additional structural anomalies

目的探讨小于胎龄且不伴结构异常胎儿与染色体和亚显微染色体异常的相关性及其临床结局。方法收集小于胎龄且不伴结构异常胎儿的染色体和亚显微染色体结果,染色体和亚显微染色体的检测方法包括染色体核型检查和染色体微阵列分析。所有病例依照是否合并母体因素、小于胎龄儿(SGA)出现孕周(32周前为早期发生、32周后为晚期发生)、合并羊水过少、脐动脉血流频谱进行分析。结果共纳入128例SGA病例,其中合并染色体核型异常6例,染色体倒位2例,致病性拷贝数变异4例,染色体核型异常和致病性拷贝数变异的检出率是7.8%(10/128)。早期发生SGA 71例,晚期发生SGA 57例。早期发生的SGA其染色体核型异常和致病性拷贝数变异的检出率较晚期发生的SGA高(P <0.05)。与晚期发生的SGA比较,早期发生的SGA母亲羊水过少及脐动脉血流频谱异常的发生率较高、分娩较早,其新生儿存活率及出生体质量也较低(P均<0.05)。合并羊水过少SGA的染色体核型异常和致病性拷贝数变异的发生率高于未合并羊水过少SGA(P <0.05)。脐动脉血流频谱正常SGA与染色体和致病性拷贝数变异的发生率与脐动脉血流频谱异常SGA比较差异无统计学意义(P> 0.05)。结论小于胎龄且不伴结构异常胎儿中,早期发生的SGA或合并羊水过少时染色体核型异常和致病性拷贝数变异的可能性明显增加。

Objective To investigate the association between the chromosomal and subchromosomal anomalies and small for gestational age(SGA) fetuses with no additional structural anomalies and assess their clinical outcomes.Methods The chromosomal and subchromosomal outcomes of all the fetuses with SGA without structural malformations were collected.Karyotyping analysis and chromosomal microarray analysis(CMA) were conducted.All cases were analyzed according to presence of maternal risk factors for SGA(yes or no),gestational age at onset of SGA(before or after 32 gestational weeks),presence of oligohydraminos or not and umbilical artery(UA) Doppler flow(normal or abnormal).Results A total of 128 SGA fetuses were enrolled.Chromosomal abnormalities were detected in 6(4.7%) SGA fetuses,chromosome inversion in 2 and subchromosomal anomalies in 4,respectively.The detection rate of chromosomal karyotype and subchromosomal anomalies was calculated as 7.8%(10/128).Among them,71 fetuses suffered from SGA in the early stage and 57 cases in the advanced stage.The detection rate of chromosomal and subchromosomal anomalies in early-onset SGA was significantly higher compared with that in the advanced stage(P <0.05).Compared with SGA in the advanced stage,the incidence of oligohydraminos and UA Doppler flow abnormality was remarkably higher,the delivery time was earlier,the survival rate of newborns was significantly lower and the birth weight was considerably less in those with early SGA(all P <0.05).The incidence of chromosomal and subchromosomal anomalies in fetuses with SGA complicated with oligohydraminos was significantly higher than that in their counterparts with SGA alone(P <0.05),whereas no statistical significance was observed between SGA with normal and abnormal UA Doppler flow(P> 0.05).Conclusion For SGA fetuses without structural anomalies,the risk of chromosomal and subchromosomal anomalies is significantly increased in those with early-onset SGA or complicated with oligohydraminos.