Experience using a rapid assay for aneuploidy and microdeletion/microduplication detection in over 2,900 prenatal specimens

Fetal Diagn Ther. 2014;36(3):231-41. doi: 10.1159/000360081. Epub 2014 Aug 8.


Background: While microarray testing can identify chromosomal abnormalities missed by karyotyping, its prenatal use is often avoided in low-risk pregnancies due to the possible identification of variants of uncertain significance (VOUS).

Methods: We tested 2,970 prenatal samples of all referral indications using a rapid BACs-on-Beads-based assay with probes for sex chromosomes, common autosomal aneuploidies, and 20 microdeletion/microduplication syndromes, designed as an alternative to microarray in low-risk pregnancies and an alternative to rapid aneuploidy testing in pregnancies also undergoing microarray analysis.

Results: Interpretable results were obtained in 2,940 cases (99.0%), with 89% receiving results in 1 day. Aneuploidies were detected in 7.3% and partial chromosome abnormalities in 0.45% (n = 13), including 5 referred for maternal age, abnormal maternal serum screen, or isolated ultrasound markers. The added detection above karyotype was 1 in 745 in lower-risk cases with normal ultrasounds or isolated ultrasound markers/increased nuchal measurements and 1 in 165 for fetuses with structural/growth abnormalities. Neither false negatives nor false positives were found within test limitations. Female polyploidy could not be detected, while polyploidies with Y chromosomes were suspected and confirmed through additional analysis.

Conclusion: When combined with karyotyping, this assay provides increased interrogation of specific chromosomal regions, while limiting VOUS identification.

MeSH terms

  • Adult
  • Aneuploidy*
  • Chromosome Duplication*
  • Cytogenetic Analysis
  • Female
  • Humans
  • Male
  • Molecular Diagnostic Techniques / statistics & numerical data*
  • Pregnancy
  • Prenatal Diagnosis / statistics & numerical data*
  • Retrospective Studies