Noninvasive Fetal Sex Determination by Real-Time PCR and TaqMan Probes

Noninvasive fetal sex determination by analyzing Y chromosome-specific sequences is very useful in the management of cases related to sex-linked genetic diseases. The aim of this study was to establish a non-invasive fetal sex determination test using Real-Time PCR and specific probes. Methods: The study was a prospective observational cohort study conducted from August 2018 to September 2019. Venous blood samples were collected from 25 Iranian pregnant women at weeks 7 to 25 of gestation. Cell-free DNA (cfDNA) was isolated from the plasma of samples and fetal sex was determined by SRY gene analysis using the Real-Time PCR technique. In the absence of SRY detection, the presence of fetal DNA was investigated using cfDNA treated with BstUI enzyme and PCR for the epigenetic marker RASSF1A. Results: Of the total samples analyzed, 48% were male and 52% female. The RASSF1A assay performed on SRY negative cases also confirmed the presence of cell-free fetal DNA. Genotype results were in full agreement with neonate gender, and the accuracy of noninvasive fetal sex determination was 100%. Conclusions: Fetal sex determination using the strategy applied in this study is noninvasive and highly accurate and can be exploited in the management of sex-linked genetic diseases.