Abstract: 【Abstract】 Objective By analyzing the methods and results of prenatal genetic diagnosis for 3 fetuses ,to explore the clinical application value of combined application for multiple genetic techniques in the identification of chromosome microstructural abnormalities. Methods The research objects were 3 pregnant women who were admitted to the prenatal diagnosis center of Beijing Haidian Maternal and Child Health Hospital from January 2016 to November 2018. All of them were found to have abnormal fetal karyotype by prenatal diagnosis, but could not be clearly diagnosed or suspected to have microstructural abnormalities. Case 1 was performed amniocentesis at 19 weeks of gestation, and the fetal karyotype was 46,XY?; Case 2 was performed umbilical vein puncture at 27 weeks of gestation, the fetal karyotype of umbilical blood was 46,XY,der (8)?; Case 3 was performed amniocentesis at 20 weeks of gestation, and the fetal karyotype was 46,XY, t(11;12)?. Chromosome G banding technique was used to analyze karyotypes. Chromosome microarray analysis (CMA) was used to detect chromosome copy number variation. Fetal metaphasechromosomes fluorescence in situ hybridization (FISH) technique was applied to detect chromosome translocations and deletions. Results The G banding karyotype of Case 1 was 46,XY,der(4)t(3;4)(p26;p16), while CMA revealed 8.1 Mb microduplication of 3p26.3p26.1 and 9.5 Mb microdeletions of 4p16.3p16.1. The karyotype of case 2 was 46,XY,t(8;12)(q22;q21.3)pat, with normal CMA results. The G banding karyotype of case 3 was 46,XY,t(11;12) (p15.5;p13.1)mat, with normal CMA results. All above results have been verified by FISH. Case 1: After genetic counseling and informed selection, the pregnant woman induced labor in the second trimester. Case 2: The follow-up result of the newborn at 3 months postpartum was normal. Case 3: The pregnant woman was still in pregnancy, and there are no ultrasound abnormality during pregnancy. Conclusions Comprehensive application of chromosome karyotype analysis, CMA and FISH technique to detect fetal and family members can enhance the reliability of results and avoid misdiagnosis or missed diagnosis.
2019, Vol. 7 
