Relationship Between Fetal Nuchal Translucency Thickness And Chromosomal Abnormalities

Objective To investigate the correlation between fetal nuchal translucency thickness(NT)and chromosome microdeletion/microrepetition during 11-13 weeks and 6 days of gestation.Method this research used the retrospective analysis.The sample is1061 pregnant women who pregnancy was 11 to 13 weeks and 6 days ultrasound screening NT in Guangxi people's Hospital between March 2016 and December2017.According to inclusion criteria and exclusion criteria,60 cases in the experimental group and 313 cases in the control group were selected.All of them were texted by fetal chorionic puncture or early pregnancy amniocentesis.The specimens were divided into two parts,one was analyzed by cell culture and chromosome karyotype analysis,and a copy was sent to a cooperative Laboratory for high throughput sequencing of chromosomes.Results In the 60 cases of NT thickening,17 cases had abnormal karyotype,and the proportion of abnormal karyotype was 30%.Among,8fetuses with trisomy21 s,3 fetuses with trisomy18 s,1 fetus with trisomy13,2fetus with 45,XO,1 fetus with 46,XY,inv(9)(p12q13),1fetus with46,XY,21 pstk,and 1 fetus with chromosomal polymorphism;In the 313 cases of control group,21 cases had abnormal karyotype,with an abnormal ratio of6.7%,including 10 fetuses with trisomy21 s mainly,1 fetus with trisomy13,5fetuses with trisomy18 s,2 fetus with 45,XO,1 fetus with 47,XXX,1fetus with47,XXY and 1 fetus with 47,XYY.The abnormal karyotype in the experimental group was statistically significant compared with that in the control group(P<0.05).The incidence of trisomy21 s syndrome in two groups was also statistically significant(P < 0.05).The other chromosomal karyotype types were not statistically significant in the two groups(P > 0.05).In the 60 samples,there were 24 cases of NT 2.5~3mm in the fetus.Among them,1 cases had abnormal karyotype,with an abnormal ratio of 4.1% and 24 cases of NT 3~4mm,7 cases of abnormal karyotype,accounting for 29.1%,12 cases of NT > 4mm,and 9cases of chromosomal karyotype,accounting for 75%.In the 60 samples of the experimental group,there were 43 cases of normal karyotype,of which 5 cases had abnormal chromosomal high sequencing analy.Conclusions The results of this study showed that the thickening of NT was associated with abnormal karyotype,especially with 21 trisomy syndrome.the thickening of NT with chromosome microdeletion /microrepetition was associated with normal karyotype.With only a single NT thickening.,CNVs detection is of little significance.