Mergenthaler Susanne, Babochkina Tatiana, Kiefer Vivian, Lapaire Olaf, Holzgreve Wolfgang, Hahn Sinuhe
Laboratory for Prenatal Medicine, University Women's Hospital, Spitalstr. 21, 4031 Basel, Switzerland.
J Histochem Cytochem. 2005 Mar;53(3):319-22. doi: 10.1369/jhc.4A6404.2005.
Current cytogenetic approaches in noninvasive prenatal diagnosis focus on fetal nucleated red blood cells in maternal blood. This practice may be too restrictive because a vast proportion of other fetal cells is ignored. Recent studies have indicated that fetal cells can be directly detected, without prior enrichment, in maternal blood samples by fluorescence in situ hybridization (FISH) analysis for chromosomes X and Y (XY-FISH). In our blinded analysis of 40 maternal blood samples, we therefore examined all fetal cells without any enrichment. Initial examinations using conventional XY-FISH indicated a low specificity of 69.4%, which could be improved to 89.5% by the use of two different Y-chromosome-specific probes (YY-FISH) with only a slight concomitant decrease in sensitivity (52.4% vs 42.9%). On average, 12-20 male fetal cells/ml of maternal blood were identified by XY- and YY-FISH, respectively.
