Rapid prenatal diagnosis of chromosome aneuploidies by interphase fluorescence in situ hybridization: a one-year clinical experience with high-risk and urgent fetal and postnatal samples.

OBJECTIVES

To evaluate the clinical utility of rapid prenatal and postnatal detection of common chromosome aneuploidies by interphase fluorescence in situ hybridization (FISH) analysis with DNA probes.

DESIGN

Four hundred and seventy-seven high-risk and/or urgent amniotic fluid, chorionic villus and fetal and postnatal blood samples were prospectively examined by FISH with probes specific for chromosomes 13, 18, 21, X, and Y and results were reported within 48 hours. All FISH results were followed by conventional chromosome analysis, if possible.

SETTING

Cytogenetic service laboratory at the tertiary referral center, Rigshospitalet in Copenhagen.

MAIN OUTCOME MEASURES

The fraction of clinically significant chromosome aneuploidies that was detected by FISH analysis, and the fraction of terminations that was based on FISH and ultrasound results rather than on conventional cytogenetic results.

RESULTS

The FISH assay detected 76% of the clinically significant chromosome abnormalities as determined by subsequent cytogenetic analysis. Seventy-two percent of the terminations of the chromosomally abnormal pregnancies were based on FISH and ultrasound results rather than on conventional cytogenetic results.

CONCLUSION

FISH analysis is a clinically useful adjunctive tool to conventional pre- and postnatal cytogenetic analysis. The assay rapidly detects the majority of clinically significant chromosome abnormalities, thus facilitating difficult pre- and postnatal clinical decisions.