Noninvasive fetal sex determination in maternal plasma: a prospective feasibility study

Abstract

Purpose: To prospectively validate a protocol for noninvasive fetal sex determination in maternal plasma and demonstrate its applicability to clinical practice. methods: Peripheral blood from 404 pregnant women undergoing prenatal invasive testing was collected from 6 to 23 weeks of gestation. Real-time PCR was performed for the SRY gene and multicopy DYS14 marker sequence located within the TSPY gene by the TaqMan minor groove binder probe assay as a first-line test. Owing to a false-positive result, amplification of repetitive motifs of the DAZ gene region was also tested as a second-line test performed in the last 232 patients enrolled in our series. A diagnostic algorithm was designed using a combination of these three markers. Fetal gender determined by noninvasive prenatal diagnosis (NIPD) was compared with that diagnosed by quantitative fluorescent PCR after invasive testing or ultrasound.Results: A single false-positive result was obtained in the first 172 pregnancies. Reporting criteria were modified in the subsequent 232 pregnancies, giving an overall sensitivity and specificity of 100% (95% CI 99.8-100%) and 99.5% (95% CI 98

Haplotype-based approach for noninvasive prenatal tests of Duchenne muscular dystrophy using cell-free fetal DNA in maternal plasma

“…Indeed, several reports of noninvasive fetal sex determination using PCRbased amplification of Y-chromosome-specific sequences, such as the DYS marker or the SRY gene, 11,12 have been published, and this method is reliable, with high sensitivity and specificity, as confirmed by numerous studies. 36,37 Considering the factors of cost and time, our future work will aim to develop specific Y chromosome probes on the capture array or to detect specific sequences on chromosome Y that can be used to estimate the fetal gender.…”

Comparative Value of Real Time and Conventional PCR in Antenatal Gender Determination

“…Although SRY gene is a single copy gene [22], it was also included in this study because it is specific to Y chromosome [22].…”

“…So early in the first trimester of pregnancy when the fetal DNA copy numbers are low, SRY gene couldn't be detected giving false negative results. Therefore, a multicopy sequence is more sensitive, efficient, and accurate than the single-copy SRY in cffDNA assessment [22].…”

“…Regarding false-negative results, the main reason for false-negative results is failure to recognize the Y-chromosome sequences, which either occur due to cffDNA low concentration at an early gestational age [14]or might be associated with different cffDNA yield by various DNA extraction methods [22].Also, it has been demonstrated that cffDNA is fragmented into <300-bp segments [34,35].However, the GeneJET is considered a male and there is 100% probability of being born a male and 100% probability to be a female if the test outcomes of the 3 genes are negative. Therefore, it is possible to apply the method presented in this study in fetal gender determination, prior to applying invasive antenatal diagnostic methods, due to its high probability of correct prediction.…”

Algorithm-Based Fetal Gender Determination Using X and Y Mini-Short Tandem Repeats at Early Gestational Ages

“…In the recent years, fetal sex has been identified by a single nonpolymorphic SRY gene (22,23). Although some clinics still prefer to use SRY for such trials, it is going to be superannuated and replaced by developed methods in which markers such as DYS14, amelogenin, X STR and Y STR are being studied, associatively or alone, using QF-PCR and QRT-PCR to reach more sensitive and specific assays (24)(25)(26)(27). Vecchione et al implemented multiplex QF-PCR, amplifying X-STR (ranged 103 -250 bp) together with amelogenin gene markers, on 26 pregnant women and considered some markers as informative markers (28).…”