荧光定量PCR技术在母体细胞污染鉴定和快速产前诊断中的应用OA

Objective To evaluate clinical application value of quantitative fluorescent polymerase chain reaction(QF-PCR)for maternal cell contamination(MCC)identification and rapid prenatal diagnosis of common chromosomal aneuploidies.Methods MCC concentration-gradient detection models were established to analyze characteristics of short tandem repeats(STR)profiles at different proportions of MCC.The incidence of MCC in 577 amniotic fluid samples was retrospectively analyzed,and detection efficacy of QF-PCR for chromosomal aneuploidies(13,18,21,X,and Y)was evaluated through comparative analysis with amniotic karyotyping results.Results In 10%or above MCC models,obviously"contamination peak"characteristics appeared the STR profiles.MCC was identified in 4 of 577 amniotic fluid samples(0.69%,4/577).Totally,60 chromosomal aneuploidies were identified out by QF-PCR,including 24 cases of trisomy 21,11 cases of trisomy 18,3 cases of monosomy X(XO),4 cases of triple X(XXX)syndrome,6 cases of Klinefelter syndrome(XXY)and 6 cases of XYY syndrome,as well as 6 additional cases of suggestive ploidy abnormalities.69 chromosomal aneuploidies were identified out by amniotic karyotyping analysis.Comparative analysis of results by QF-PCR with those by amniotic karyotyping revealed full concordance for 52 cases of non-mosaic aneuploidies,and the discrepancies included:two cases of Y-chromosome structural rearrangements were misclassified as XYY by QF-PCR;for six sex chromosome mosaicism cases,QF-PCR suggested ploidy anomalies only but failed to resolve mosaic composition;and nine undetected cases of balanced rearrangements and deletions/duplications attributed to QF-PCR kit limitations.Conclusion QF-PCR can effectively identify out MCC at≥10%thresholds and exerts such advantages as rapid diagnosis and high sensitivity for common chromosomal aneuploidies.However,limitations persist in detecting chromosomal mosaicism composition,balanced translocations and copy number variations(CNVs).So,QF-PCR could be used as an adjunctive screening tool for prenatal aneuploidy diagnosis in clinic.