A comparative study of standard cytogenetic evaluation and molecular karyotyping for products of conception.

Abstract

Genetic analysis of fetal tissue provides valuable information regarding the underlying causes of miscarriage. However, current analysis techniques are limited and expensive. This trial compared a molecular multiplex, bead-based suspension array, KaryoLite Bacs on Beads, with conventional tissue culture and G-banded karyotype techniques. A 92% overall success rate was achieved. This method detected a cryptic deletion of a 7q subtelomeric region, a case of 25% mosaic trisomy 14, and 2 unbalanced subtelomeric rearrangements due to familial balanced translocations. Twenty (24%) of the 83 samples analyzed, that failed to yield a cytogenetic result due to culture failure, were successfully assayed using the suspension array. Genomic imbalances including trisomies and subtelomeric deletions were detected in 3 cases (15%) of previously failed cases. This method is limited by its inability to detect polyploidy, which is significant in first trimester loss. However, this can be readily overcome by prescreening using florescent in situ hybridization. Data indicates that KaryoLite BoBs molecular testing is superior to conventional cytogenetic evaluation in several key areas, including success rate (95% vs. 76%, for this study group), cost, turnaround time (2 vs. up to 28 d), and subjective result interpretation.