High-resolution Chromosomal Microarray with Diagnostic Potential for Detecting Exon-level Copy Number Variations...

Area of Science:

• Genetics
• Molecular Biology
• Clinical Diagnostics

Background:

• Copy number variations (CNVs) are significant contributors to human genetic disorders.
• Accurate detection of exon-level CNVs is critical for clinical diagnosis.
• The CytoScan XON Array is a new high-resolution microarray designed for exonic CNV detection.

Purpose of the Study:

• To evaluate the clinical performance and diagnostic utility of the CytoScan XON Array.
• To compare the array's performance against orthogonal methods and genome sequencing (GS)-based CNV callers.
• To assess the array's reliability in detecting exon-level CNVs.

Main Methods:

• Clinical evaluation using 59 patient samples with pre-identified CNVs.
• Orthogonal validation via multiple ligation-dependent probe amplification (MLPA), gene-dose PCR, and mRNA assays.
• Comparison with GS-based CNV calling tools for non-target regions and false-positive analysis.

Main Results:

• High concordance rates for the CytoScan XON Array: 89.8% at the exon level and 92.5% at the gene level in target regions.
• Superior concordance for multi-exon CNVs (100%) compared to single-exon CNVs (82.6%).
• Reduced false-positive CNV calls in non-target regions (<0.01 per gene per person) and comparable performance to GS tools in dosage-sensitive genes.

Conclusions:

• The CytoScan XON Array is a reliable tool for detecting exon-level CNVs in targeted regions.
• It serves as a valuable complement to GS-based CNV calling tools for high-resolution, genome-wide screening.
• Further optimization for single-exon CNV detection and cross-validation with GS tools are recommended for enhanced diagnostic accuracy.