Prenatal diagnosis of common aneuploidies in transcervical samples using quantitative fluorescent-PCR analysis

The aim of this study was to test the feasibility of diagnosing common fetal chromosomal aneuploidies using quantitative fluorescent (QF)-PCR on transcervical cell (TCC) samples collected in the first trimester of pregnancy by means of intrauterine lavage (IUL).

A total of 181 TCC samples were retrieved from pregnant women between 5 and 12 weeks of gestation, immediately before elective termination of pregnancy, at which time corresponding placental tissue and maternal blood specimens were also obtained. Isolation of trophoblastic cells by micromanipulation was attempted in all TCC samples. Micromanipulated specimens were analyzed by multiplex QF-PCR, including short tandem repeats for the chromosomes X, Y, 21, 18, and 13.

The micromanipulation was successful in 152 of 181 cases (84.8%) where chorionic villous filaments and/or cell clumps of seeming trophoblastic origin could be isolated. All 152 samples were tested by QF-PCR analysis and peaks of paternal origin could be documented in all cases. Two cases of trisomy 21 and two cases of monosomy X0 were detected by means of QF-PCR assay, in accordance with the results obtained in corresponding placental samples.

This study provides evidence that the use of multiplex QF-PCR amplification of selected microsatellites could be applied to micromanipulated TCC samples and in particular to IUL samples, which often contain trophoblastic cells, for the detection of chromosomal aneuploidies. The approach described in this study appears, therefore, a very promising tool toward non-invasive prenatal genetic diagnosis in the early stage of gestation.