Fluorescence in situ hybridization in uncultured amniocytes for detection of aneuploidy in 4210 prenatal cases

Background Almost all reported fluorescence in situ hybridization (FISH) kits for prenatal diagnosis use probes from foreign (non-Chinese) countries. The aim of this study was to analyze the reliability of domestic (Chinese) FISH probe sets to detect aneuploidies of chromosomes 13, 18, 21, X, and Y related to prenatal diagnosis in 4210 cases.Methods Cytogenetic karyotyping was carded out as a standard prenatal diagnostic test, and amniotic fluid cell interphase FISH analysis was performed using two sets of probes (centromeric probes for chromosomes 18, X, and Y,and locus-specific probes for chromosomes 13 and 21) provided by GP Medical Technologies, Beijing, China. Then we compared the two results and found the performance characteristics for informative FISH results of aneuploidies by the domestic kit probes.Results In 4210 cases, 4126 cases generated karyotype results and 133 abnormal karyotypes (including 97 aneuploidies) were found. The FISH results of 98 cases (among them, 31 cases gave normal cytogenetic results) were uninformative. The rate of abnormal cases was 3.2% (133/4126). For the abnormal karyotypes, the rate of aneuploidy was 72.9% (97/133). Among the 97 aneuploidies, there were 58 cases of trisomy 21 (58/97, 59.8%), four cases of trisomy 13, 23 cases of trisomy 18, and 12 cases of sex chromosomal aneuploidies. The total concordance of the two methods was 97.9% (95/97; two cases were mosaics that had a low percentage of abnormal cells), and the concordance of trisomy 21, 13, and 18 by the two methods was 100%.Conclusions The two sets of the domestic FISH kit probes are reliable for prenatal diagnosis. The results demonstrate that FISH is a rapid and accurate clinical method for prenatal identification of chromosome aneuploidies.