Résumé
Objective@#To investigate the value of karyotype analysis, bacterial artificial chromosomes-on-beads (BoBs), chromosome microarray analysis (CMA) and fluorescence in situ hybridization (FISH) in the diagnosis of sex chromosome numerical and structural abnormalities.@*Methods@#Conventional G-banding staining technique was used to analyze the karyotypes of amniotic fluid cells and parental peripheral blood cells in two pregnancies with prenatal diagnosis indications. Sex chromosome numerical and structural abnormalities were analyzed based on the results of G-banding, BoBs, CMA and FISH.@*Results@#The results of G-banding karyotype analysis showed that there were mosaics in amniotic fluid cells collected from both cases. Karyotype of Case A was 45,X[25]/46,X,idic(Y)(q11.2?)[6], and Case B was 45,X[39]/46,X,psu idic(X)(q21.32?)[44]. Parental peripheral blood karyotypes of both families were normal. Prenatal BoBs indicated copy number abnormalities in sex chromosomes (Y chromosome in Case A and X chromosome in Case B). CMA results suggested a 20.1 Mb duplication in Yp11.32q11.222, and a 7.7 Mb deletion in Yq11.222q11.23 in fetus A with possible karyotype of 46,X,idic(Y)(q11.222); for fetus B, a 92.0 Mb duplication in Xp22.33q21.32, and a 63.0 Mb deletion in Xq21.32q28 were detected, and the karyotype might be 46,X,psu idic(X)(q21.32). The mid-term FISH test of amniotic fluid cells showed that 90% of the amniotic cells from Case A were 45,X, and 10% were 46,X,idic(Y)(q11.2); about 38% were 45,X, and 62% were 46,X,psu dic(X)(q21.3) from Case B.@*Conclusions@#Numerical and structural abnormalities of sex chromosomes could be accurately diagnosed by combination of several methods including G-banding karyotype analysis, prenatal BoBs, CMA and FISH, which would help to effectively reduce birth defects.
Résumé
Objective To investigate the effect of maternal age,gestational weeks,numbers of previous spontaneous abortion and embryo gender on chromosomal abnormalities.Methods Bacs on Beads (BoBs) technology was used to detect the chromosome aneuploidy of 245 pregnant women with spontaneous abortion or stillbirth in Jinan Maternity and Child Care Hospital from January 2015 to December 2017 and to analyze the types of their chromosome abnormalities.Comparative analysis between different groups was carried out using Chi-square test.Results Karyotypes of all cases (n=245) were obtained using BoBs.Among them,113 had chromosome abnormalities (46.1％),including 66 autosomal aneuploidy (58.4％),26 sex chromosome aneuploidy (23.0％),seven autosomal partial trisomy (6.2％),five autosomal partial monomer (4.4％),seven triploid (6.2％),one complex triploid (0.9％) and one double trisomy (0.9％).Pregnant women aged over 35 had a higher incidence of chromosome abnormality than those under 35 [61.0％ (36/59) vs 41.4％ (77/186),x2=8.003,P＜0.05].The incidence of chromosome abnormality of women aborted in the first-trimester was also higher than those aborted in the second-trimester [48.5％ (99/204) vs 34.2％ (14/41),x2=4.634,P＜0.05].Moreover,male embryos were more likely to have chromosome abnormality than female ones [57.6％ (49/85) vs 40.0％(64/160),x2=6.483,P＜0.05)].However,there was no significant difference between gravidas with different times of spontaneous abortion (0,1 or ≥ 2,P＞0.05).Conclusions Chromosome abnormality is a major cause of spontaneous abortion,particularly in embryos with chromosome aneuploidy,partial trisomy,partial monomer and triploid.Advanced maternal age may increase the risk of chromosome abnormalities in pregnancies complicated with spontaneous abortion or stillbirth.
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Objective To evaluate a new prenatal diagnosis model of chromosomal abnormalities and nine microdeletion syndromes by using both traditional karyotyping and a newly-developed rapid prenatal diagnosis technology, BACs-on-Beads (BoBs) technique. Methods From June 2012 to December 2014, 807 pregnant women with high risk after screening or with other indicators, were performed amniocentesis. Traditional karyotyping and BoBs were employed simultaneously for prenatal diagnosis. Results Thirty-two cases with chromosome aneupoidies were successfully detected both by BoBs and karyotyping, including 18 cases of trisomy 21, 6 cases of trisomy 18, 1 case of trisomy 13, and 7 cases with sex chromosome abnormality. All 8 fetuses with chromosome structural abnormalities detected by karyotyping were missed by BoBs;while BoBs contributed more in detection of five microdeletion syndrome cases, including 3 cases of DiGeorge syndromes (two with microduplication and one with microdeletion), one case of Miller-Dieker syndrome, and one case of Wolf-Hirschhorn syndrome. Conclusion Combined use of traditional karyotyping and BoBs, is a rapid and effective prenatal diagnosis model that may enlarge our horizon on chromosomal diseases and should be widely used in future clinical service.
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Objective To evaluate the quality of BAC clones for CGH microarrays in the detection of tumors.(Methods Chromosome) preparations were made from peripheral blood of the healthy volunteers in the conventional manner.The locations of BAC(RPCI-11 library and CTC library) within the region of interest were compiled from information archived by the UCSC and the NCBI.Probes were labeled by nick-translation with biotin-16-dUTP or digoxigenin-11-dUTP.Precise localization of each BAC was confirmed using normal metaphase chromosomes by FISH technique.The copy number and molecular organization of the region of 223 BAC clones which were crucial in the development and progression of human cancers were investigated.Results The FISH analysis indicated the normal BAC clones accounted for 81.62% of the total(186/223);the abnormal clones with additional FISH noises accounted for 13.45%(30/223);those with wrong localization pattern was 3.58%(8/223),and those with no bacterial growth was 1.35%(3/223),respectively.Conclusion FISH technique is effective and useful in the identification of BAC clones for array CGH.