[Application of fluorescence in situ hybridization to prenatal diagnosis of aneuploidy in 110 uncultured amniotic fluid samples].

OBJECTIVE: To optimize the prenatal diagnosis platform by using domestically made fluorescence in situ hybridization(FISH) kit and to explore the clinical application of FISH to rapid prenatal diagnosis of a wide range of chromosomal abnormalities. METHODS: Amniotic fluid samples from 110 pregnant women were studied with the rapid prenatal diagnosis method of FISH and the conventional cell culture method of karyotyping, the results from both methods were compared. RESULTS: Four cases of trisomy 21, 1 case of trisomy 18, 58 cases of 46, XX, and 47 cases of 46, XY were detected by FISH in the 110 amniotic fluid samples. It is concordant with the results from conventional karyotype analysis. The concordance rate is 100%. CONCLUSION: Domestically made FISH kit can be used to rapidly and accurately detect the most common chromosome aneuploidies by using less sample volume while the price is relatively low. FISH can be a reliable and rapid prenatal diagnostic tool as an adjunct to classical cytogenetic study. It can be used for rapid and accurate prenatal diagnosis of women with high risk of maternal serum screening.

[Application of array-based comparative genomic hybridization in precise diagnosis of unbalanced chromosome aberration].

OBJECTIVE: To evaluate the method of array-based comparative genomic hybridization (array-CGH) in identifying unbalanced chromosome aberrations. METHODS: Four cases that could not be diagnosed by conventional cytogenetic technique were selected to undergo array-CGH analysis. DNA samples were extracted and hybridized with the Affymetrix SNP 6.0 arrays using Human Mapping SNP6.0 assay kit following the manufacturer's standard protocol. The data were analyzed by two professional software packages, GCOS and Genotyping Console. RESULTS: By using array-CGH technique, all the four cases were diagnosed precisely through identifying two duplications and two complex derivative chromosomes. CONCLUSION: Array-CGH is an effective method for whole-genome identification of unbalanced chromosomal aberrations with high sensitivity and specificity. It has a great value to investigate the correlations between genotype and phenotype in clinical service, especially in prenatal diagnosis.

[Application of spectral karyotyping in diagnosis and prenatal diagnosis of the marker chromosome].

OBJECTIVE: To determine the value of spectral karyotyping(SKY) in identification of the marker chromosome. METHODS: Selected six cases that could not be identified in clinic were studied, using samples of peripheral blood from four cases, and samples of amonic fluid and fetal cord blood for prenatal diagnosis in two cases were investigated. All cases were analyzed with the routine SKY method, and the results with the SKY View software. The SKY results were identified by using fluorescence in situ hybridization (FISH). And C-banding technique was used to help diagnose the heterochromatin. RESULTS: SKY was successfully performed on all of 6 cases. The origin of all marker chromosomes was identified by SKY. Except case No. 4, the others were confirmed by FISH. It helped determine the pregnancy outcome in two cases of prenatal diagnosis: one case of genetic marker chromosome continued the pregnancy, and another case of de novo marker chromosome was terminated of the pregnancy. CONCLUSION: SKY may be a valuable tool to diagnose the marker chromosome with rapidness,direct-viewing and sensitiveness. It can be used to assess the prognosis and the pregnancy outcome.