Rapid prenatal diagnosis of Down syndrome and Edward syndrome by fluorescence In situ hybridization:Clinical experience with 309 cases

ABSTRACT

PURPOSE: The purpose of this study was to evaluate the clinical utility of rapid detection of Down syndrome and Edward syndrome by Interphase Fluorescence in Situ Hybridization (FISH) analysis METHODS: A retrospective study in 309 cases of amniotic fluid samples, analysed by interphase FISH with DNA probes specific to chromosome 18 and 21, was performed. All FISH results were compared with conventional cytogenetic karyotypings. RESULTS: The results were considered as informative and they were obtained within 48 hrs. A case of Down syndrome and a case of Edward syndrome were diagnosed by FISH and confirmed by subsequent cytogenetic analysis. In 12 cases with normal FISH results, the cytogenetic analysis showed a case of partial trisomy 22, three cases of sex chromosomal aneuploidy, two cases of mosaicism, two cases of microdeletion, and four cases of structural rearrangement. CONCLUSION: FISH is a rapid and effective diagnostic method, which can be used as an adjunctive test to cytogenetic analysis, for prenatal identification of chromosome aneuploidies. For the more genome- wide screening with variety of probes, the technique of FISH is both expensive and labor-intensive.