OBJECTIVETo evaluate the feasibility of rapid prenatal diagnosis of chromosome aneuploidies by interphase fluorescence in situ hybridization (FISH) using uncultured amniotic fluid.

METHODSBacterial artificial chromosome (BAC) DNA probes were prepared and validated by using cultured peripheral blood. Interphase FISH for chromosomes 13, 18, 21, X and Y was performed in 60 amniotic fluid samples for the rapid prenatal diagnosis of chromosome aneuploidies, and the results were compared with the karyotypes from conventional cytogenetic analysis.

RESULTSOf all 60 cases, 58 were concordant with their karyotypes, and 1 case of inv(9) and another case of t(2,12) were identified by karyotyping. Two cases of trisomy 21 and 1 case of trisomy 18 were detected by FISH and confirmed with conventional cytogenetics (sensitivity=100%). There were no false-positive or false-negative results.

CONCLUSIONThis evaluation demonstrated that FISH employing BAC DNA probes could accurately and rapidly detect aneuploidies involving the above 5 chromosomes. However, as it does not identify structural chromosome aberrations and aneuploidies involving other chromosomes, it is not a substitute for conventional chromosome analysis, and the negative FISH result should be carefully interpreted.