Rapid Detection of Aneuploidies in Spontaneous Aborted Fetal Samples by Quantitative Fluorescence-PCR: A Descriptive Study

Chromosomal aneuploidies are the most chromosomal abnormalities at birth due to maternal meiosis I errors. Pregnancies with autosomal chromosomal aneuploidies that survive are namely trisomies ۱۳ (Patau syndrome), ۱۸ (Edward syndrome), and ۲۱ (Down syndrome), account for ۸۹% of chromosome abnormalities. Quantitative fluorescent polymerase chain reaction (QF-PCR) which amplifies specific DNA sequences called short tandem repeats (STRs), by using fluorescently labeled primers is a rapid technique for prenatal diagnosis of common aneuploidies. In this study, DNA extraction was performed from ۱۰۰ samples isolated from muscle tissue of aborted fetuses. The analysis was performed by multiplex QF-PCR using a panel of ۲۵ STRs markers for chromosomes X, Y, ۱۳, ۱۸, and ۲۱. Our results showed that ۲۰% of abortions were due to aneuploidy. ۵۳% of mothers who had abortions were aged ۲۶-۳۵ years old and ۳۲% of them were aged ۳۶-۴۵ years old. The analysis of muscle samples of aborted fetuses indicated that ۲۰ samples showed chromosomal aneuploidy. Of the abnormal cases, ۱۰ cases (~۵۰ %) showed trisomy ۲۱ followed by trisomy ۱۸ (۷ cases, ~۳۵%), Klinefelter syndrome (۲ cases, ~۱۰ %), and showed trisomy X (۱ case, ~۵ %). Our results indicated that the D۲۱S۱۴۱۴ marker showed the highest rate of heterozygosity in the study population. Besides some limitations of this study such as sample size, these results suggest that one of the causes of these abortions could be maternal age. We concluded that QF-PCR could be a rapid and reliable method to screen prenatal chromosomal aneuploidy and allow appropriate counseling.

Keywords:

Abortion , Chromosomal aneuploidy , Fetus , Iranian population , QF-PCR