Chromosomal anomalies in early spontaneous abortions: interphase FISH analysis on 855 FFPE first trimester abortions.

Abstract

Cytogenetic analysis of spontaneous abortuses presents at least two main challenges, cell culture failure, and excess of normal female karyotypes related to maternal cell contamination (MCC). Molecular cytogenetic techniques using uncultured cell suspension overcome cell culture failure, but do not resolve MCC at all. The aim of the present study is to demonstrate that interphase fluorescence in situ hybridization (FISH) on routine formalin-fixed paraffin embedded (FFPE) abortive materials is an efficient method to identify chromosomal anomalies in abortuses and to detect MCC. Interphase FISH with a panel of eight probes was applied on 855 FFPE consecutive early spontaneous abortions. Male/female ratio was 0.88 in the complete sample, 0.9 in the group of negative FISH result, and 0.8 in the group with abnormal FISH results, suggesting that no gender predominance was present in our data. The aneuploidy rate was 50.3%. Autosomal trisomies were 60%, polyploidies 23.2%, and X monosomy 14%. Chromosomal mosaicism was discovered in 1.9% with six cases of confined placental mosaicism. FISH on FFPE abortion materials appears to be a successful approach to detect chromosomal anomalies in abortions. Moreover, the preservation of the tissue morphology allows the analysis of only the fetal cells, making the presence of maternal tissues irrelevant.