Prenatal Screening for Aneuploidy in Iranian Families Using QF-PCR

Quantitative fluorescence polymerase chain reaction (QF-PCR) has been introduced in a number of genetic laboratories as an inexpensive, rapid and reliable method for prenatal recognition of aneuploidy in chromosomes 13, 18, 21, X and Y. We have investigated the efficacy of QF-PCR for the prenatal recognition of common aneuploidy and compared our findings with cytogenetic results in Iran. A multiplex PCR involving 15 short tandem repeat (STR) sequences was established for aneuploidy screening and chromosomal study was performed for all samples as well. Finally, the results obtained from QF-PCR method and cytogenetic analysis were compared with each other. A total of 425 prenatal samples were analyzed including 393 amniotic fluid and 25 chorionic villus samples (CVS). The following abnormalities were detected in 13 individuals: 6 samples (1.41%) with Down syndrome, 2 samples with Edward syndrome (0.47%), and 3 samples with Patau syndrome, 47, XXY, and 47, XYY. All of the CVS samples were normal. In addition, 2 cases (0.47%) showed triploidy. We were able to detect all the aneuploidies of chromosomes 13, 18, 21, X and Y and this was confirmed by cytogenetic results. Contamination of the fetal specimens by maternal cells was present in 12 out of 425 samples (2.82%) and failed to obtain any results. Additional chromosomal abnormalities were detected in 3 cases by karyotyping: inversion 9, translocation t(9,14) and XX/XY mosaicism. Through the QF-PCR method, we were able to detect abnormalities in 96.47% of all referred families. We recommend the QF-PCR in combination with cytogenetic study to be performed on all prenatal cases to provide a rapid and reliable diagnosis in families at risk for aneuploidy. We also recommend all the families that are seeking prenatal diagnosis of single gene disorders a QF-PCR to be added to their work up.