| Objective:Understand the detection rate of chromosomal abnormalities and the types of chromosomal abnormalities under different prenatal diagnosis indications;understand the value of chromosome microarray analysis(CMA)in detecting chromosome micro-deletion/micro-duplication.Methods:The data of 1857 pregnant women who underwent prenatal diagnosis in our hospital due to different prenatal diagnosis indications were collected from October 2018 to October 2020.All pregnant women underwent amniotic fluid chromosome karyotype analysis,and 53 of them underwent chromosome microarray analysis at the same time(CMA).The prenatal diagnosis indications involved include:(1)Non-invasive prenatal testing(NIPT)high risk(including 21/18/13-trisomy,abnormal number of sex chromosomes and high risk of other chromosomal abnormalities);(2)advanced age(pregnant women)Age≥35 years old);(3)High risk of serological screening;(4)Abnormal ultrasound or soft index;(5)History of bad pregnancy and childbirth;(6)Pregnant woman or her spouse is a carrier of chromosomal abnormality;(7)Other reasons(including history of medication in early pregnancy or history of adverse exposure,etc.).Results:1.Among the 1857 pregnant women with amniotic fluid chromosome karyotypes,a total of 269 abnormal karyotypes were detected,with a total detection rate of14.49%.Among them,there were 223 cases with abnormal number of chromosomes,the detection rate was 12.01%,accounting for 82.90%of abnormal karyotypes,including:21-trisomy 150 cases;18-trisomy 35 cases;13-trisomy 6 cases;sex chromosome number abnormal 21 Cases;11 cases of chimera.There were 46 cases of abnormal chromosome structure,the detection rate was 2.48%,accounting for 17.10%of abnormal karyotypes,including:18cases of translocation;14 cases of partial chromosome duplication;11 cases of partial chromosome deletion;3 cases of inversion.The difference between the detection rate of abnormal number and abnormal structure was statistically significant(χ~2=6.437,P<0.05).2.The detection rates and abnormal types of chromosomal abnormal karyotypes under different indications are as follows:(1)NIPT has 263 high-risk cases,163cases of abnormal karyotypes are detected,and the detection rate is 61.98%,including 99 cases of trisomy 21,18-There were 27 cases of trisomy,4 cases of13-trisomy,20 cases of abnormal number of sex chromosomes,6 cases of mosaicism,5 cases of partial chromosome deletion;2 cases of partial chromosome duplication;(2)643 cases of advanced age(pregnant woman age≥35 years),59 cases of abnormal karyotype were detected,the detection rate was 9.18%,including 41 cases of 21-trisomy,4 cases of 18-trisomy,2 cases of13-trisomy,2 cases of mosaicism,1 case of partial chromosome deletion,and partial chromosome duplication 6 cases,1 case of translocation,2 cases of inversion;(3)715 cases of high-risk serological screening,22 cases of abnormal karyotype were detected,the detection rate was 3.08%,including 9 cases of 21-trisomy,18-three 3 cases of body,2 cases of mosaicism,1 case of partial chromosome deletion;5 cases of partial chromosome duplication,2 cases of translocation;(4)57 cases of abnormal ultrasound or soft index,5 cases of abnormal karyotype were detected,the detection rate was 8.77%,including 1 case of 21-trisomy,1 case of 18-trisomy,1 case of abnormal number of sex chromosomes,1 case of partial chromosome deletion;1 case of translocation;(5)120 cases of poor pregnancy and childbirth,with abnormal karyotype detected 3 cases,the detection rate was 2.50%,including 2 cases of partial chromosome deletion;1 case of partial chromosome duplication;(6)31 cases of pregnant women or their spouses were chromosome carriers,17 cases of abnormal karyotype were detected,and the detection rate was 54.84%.Including 1 case of mosaicism,1 case of partial chromosome deletion;14 cases of translocation,1 case of inversion;(7)28 cases of other reasons group(including history of medication in early pregnancy or history of adverse contact,etc.),no chromosomal abnormalities were detected.The difference in the detection rate of chromosomal abnormal karyotypes under various indications was statistically significant(χ~2=629.536,P<0.05).3.53 pregnant women who underwent amniotic fluid karyotype analysis and CMA test at the same time(including 29 high-risk NIPT cases,12 cases with abnormal ultrasound or soft index,4 cases with pregnant women or their spouses as carriers of balanced chromosome translocation,3 cases with advanced age,serum(3 cases of high-risk medical screening,2 cases of adverse pregnancy history):Amniotic fluid karyotype analysis and CMA detected 16 cases of chromosomal abnormalities,the total detection rate is 30.19%,including 1 case of 21-trisomy,1 case of 18-trisomy,and 1 case of 21-tris There were 9 cases of partial chromosome deletion/duplication(fragment size range 0.15Mb～33.4Mb),1 case of loss of heterozygosity,and 3 cases of balanced translocation/inversion.Among them,1 case of 21-trisomy,1 case of 18-trisomy,1 case of 21-trisomy mosaicism,and 5 cases of partial chromosome deletion/duplication(fragment>5Mb)were detected by both;3 cases of balanced translocation/Inversion was only detected by amniotic fluid chromosome karyotype analysis;4 cases of microdeletion/microduplication(fragment<5Mb)and 1 case of loss of heterozygosity were only detected by CMA.In addition,for the 5 pregnant women with chromosomal abnormalities detected by CMA,the main prenatal diagnostic indications were NIPT indicating high risk of other chromosomal abnormalities,advanced age,and ultrasound abnormalities.The chromosomal abnormalities suggested by CMA all involve the OMIM gene and are related to pathogenicity.Chromosomal abnormalities are related.Conclusion:1.All pregnant women with indications for prenatal diagnosis are recommended to undergo amniotic fluid karyotype analysis to determine whether there is an abnormal fetal karyotype.Among all the prenatal diagnosis indications,the detection rate of amniotic fluid chromosome abnormalities is higher when NIPT is at high risk and when pregnant women or their spouses are carriers of chromosomal abnormalities.The karyotype abnormalities detected under various prenatal diagnosis indications include abnormal chromosome number as well as abnormal chromosome structure.2.Chromosome microarray analysis(CMA)can not only detect chromosomal aneuploidy,but also detect chromosome microdeletion and microduplication(fragment<5Mb).For pregnant women with high risk of other chromosomal abnormalities,advanced age,ultrasound abnormalities or soft indicators that NIPT suggests,amniotic fluid chromosome karyotype analysis and CMA testing should be performed at the same time to improve the detection rate of chromosomal abnormalities. |
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