Aneuploidy screening in a coelomic sample from a missed abortion using sequential fluorescence in situ hybridization.

OBJECTIVE

To investigate the incidence of aneuploidy by using sequential interphase fluorescence in situ hybridization (FISH) in an uncultured coelomic fluid sample from a missed abortion.

DESIGN

Case report.

SETTING

Fetal medicine and gynecology departments of two university hospitals.

PATIENT(S): A 33-year-old woman with a missed abortion.

INTERVENTION(S): Molecular cytogenetic analysis was performed on coelomic fluid cells and placental tissue by applying a multicolor probe for chromosomes 13, 16, 18, 21, and 22 in a first layer of hybridization, followed by a triple-color probe for chromosomes X, Y, and 18.

MAIN OUTCOME MEASURE(S): Analysis of limited number of coelomic cells by using sequential FISH.

RESULT(S): The results showed trisomy 13 in 92% of nuclei. Diploid cells were observed at low levels (4%), but these were caused by maternal cell contamination, as revealed after reprobing with the X,Y,18 triple-color probe set. The result also was confirmed in the placental tissue.

CONCLUSION(S): We conclude that sequential FISH analysis can overcome problems associated with limited cell numbers, accurately detect aneuploidy, and distinguish between maternal cell contamination and genuine mosaicism in coelomic cells and placental tissue from missed abortions. It also has the potential to be applied for rapid aneuploidy screening in clinical cases after coelocentesis and to be used for follow-up analysis of pregnancies established after preimplantation genetic screening.