The application value analysis of non-invasive prenatal testing in fetal chromosomal copy number variation
Objective To explore the clinical significance and application value of non-invasive prenatal testing(NIPT)technology in prenatal screening for fetal chromosomal copy number variations(CNVs).Methods 224 pregnant women who underwent NIPT testing at Huai'an Maternal and Child Health Hospital from January 2018 to July 2021,with results suggesting possible fetal CNVs,were selected as the study subjects.Amniocentesis and further prenatal diagnosis[amniotic fluid karyotyping and chromosome microarray analysis(CMA)]were performed in 171 of these pregnancies,and 171 fetal amniotic fluid samples were obtained.The results of amniotic fluid karyotyping and CM A were compared and analyzed with the results of NIPT and followed up.Results According to the grouping of different types of CNVs,the microdeletion group accounted for 54.02％(121/224)of all CNVs,the microduplication group accounted for 39.73％(89/224)of all CNVs,and the microdeletion-combined-microduplication group accounted for 6.25％(14/224)of all CNVs,the positive predictive values of amniocentesis in the microdeletion group,the microduplication group,and the microdeletion-combined-microduplication group were 56.67％,50.70％and 80.00％,respectively,and the difference in positive predictive value among the three groups was not statistically significant(X2=3.412,P＞0.05).According to the grouping of different segments of CNVs,＞10Mb group accounted for 18.75％(42/224)of all CNVs,5-10Mb group accounted for 20.54％(46/224)of all CNVs,＜5Mb group accounted for 60.71％(136/224)of all CNVs,the positive predictive value of amniocentesis in＞10Mb group,5-10Mb group,＜5Mb group were 56.76％,60.00％and 53.54％,respectively,and the difference in positive predictive value among the three groups was not statistically significant(x2=0.465,P＞0.05).Among the 95 fetal CNVs diagnosed after amniocentesis for chromosomal karyotyping and CM A,pathogenic CNVs accounted for 33.68％(32/95),probable pathogenic CNVs accounted for 21.05％(20/95),CNVs of uncertain significance accounted for 41.05％(39/95),probable benign CNVs accounted for 4.21％(4/95),and there were no benign CNVs cases.224 pregnant women whose NIPT suggested fetal CNVs were followed up by telephone or outpatient,the follow-up rate was 86.16％(193/224).However,the follow-up rate of pregnant women who underwent amniocentesis was 100.00％.A total of 5 pregnant women who chose to continue their pregnancy among pathogenic CNVs were found to have CNVs of maternal origin in 3 cases verified by CMA of the parents,2 cases refused to be verified,and none of the 5 neonates showed any obvious abnormal phenotype.There were 10 cases of pregnant women who chose to continue pregnancy among the potentially pathogenic CNVs,3 cases were found to have CNVs of paternal origin,maternal origin,and new mutations,respectively,by CMA of the parents,and 7 cases refused to be verified.Conclusion The application of NIPT for the preliminary screening of fetal CNVs is effective and feasible,and standardized ultrasound screening and invasive prenatal diagnosis must be recommended for pregnant women with possible CNVs indicated by NIPT.
万方数据
维普
