Increased Y-chromosome detection by SRY duplexing.

Area of Science:

• Molecular Biology
• Genetics
• Prenatal Diagnostics

Background:

• Noninvasive fetal sex determination relies on accurate Y-chromosome detection.
• Existing assays can struggle with low cell-free fetal DNA (cfDNA) concentrations or chimerism.
• A robust assay is crucial for reliable prenatal genetic analysis.

Purpose of the Study:

• To develop a novel, highly sensitive assay for Y-chromosome detection.
• To improve the detection of Y-chromosome material at low cfDNA concentrations.
• To create a duplex assay combining a new SRY assay with a literature-based SRY assay.

Main Methods:

• Analysis of 48 plasma samples from pregnant women (gestational weeks 5-35).
• Fetal sex determination using DYS14 and SRY assays.
• Comparison of two monoplex SRY assays against a novel SRY duplex assay at low DNA concentrations.

Main Results:

• The DYS14 assay demonstrated higher sensitivity but lower specificity than the SRY assay at low cfDNA levels.
• The developed duplex SRY assay achieved enhanced sensitivity while maintaining the specificity of monoplex assays.
• The duplex assay proved more effective in detecting Y-chromosome material in challenging low-concentration samples.

Conclusions:

• The novel SRY duplex assay significantly improves Y-chromosome detection sensitivity at low DNA concentrations.
• This advancement enhances the reliability of noninvasive fetal sex determination.
• The duplex assay offers a more robust solution for detecting Y-chromosome material in cfDNA analysis.