Multiplex interphase FISH as a screen for common aneuploidies in spontaneous abortions

BACKGROUND: A multiplex fluorescence in-situ hybridization (FISH) strategy using chromosome-specific probes for eight chromosomes as an initial screen for chromosome abnormalities in uncultured tissues from spontaneous abortions was evaluated. METHODS: Fifty-seven prefetal spontaneous abortions were studied by karyotyping cultured cells and using FISH on uncultured cells. Two probe sets were used, identifying chromosomes 13, 15, 16, 18, 21, 22, X and Y. RESULTS: Abnormalities were detected in 53% of cases by karyotyping, and 54% of cases by FISH. FISH detected an abnormality in four of five cases where cultures failed, and in two cases where maternal cells apparently overgrew the culture. FISH missed four trisomies not identifiable with the probe sets, and one trisomy because one probe set was unscorable. FISH using these probes identified 83% of all abnormalities detected by karyotyping. CONCLUSIONS: FISH can detect abnormalities in a significant proportion of cases where the culture fails to grow or is contaminated by maternal cell growth. Multiplex FISH as an initial screen, followed by culture and karyotyping in cases where no abnormality is detected, would identify a higher proportion of chromosome abnormalities in spontaneous abortion specimens than karyotype analysis alone.