Targeted Mosaic Variant Testing

Casandra

Casandra Test Code GE31438Version 1 (DRAFT)

Performing Lab

Lab GeneDxLab Test ID N/A

Targeted Mosaic Variant Testing

Clinical Use

Use

Targeted Mosaic Variant Testing is intended to evaluate for mosaicism for a known familial variant previously identified in an individual or family member. Clinical scenarios include clarifying reproductive risk in parents when a variant is identified in a child, testing a parent suspected to be mosaic due to mild or tissue‑specific features, assessing tissue‑specific mosaicism in a proband, and confirming suspected mosaic findings identified in research. This targeted testing applies to sequence variants (excluding CNVs).

Special Instructions

Ordering requires a requisition form; the form must accompany the specimen or testing may be canceled or delayed. Specify the gene name and specific variant for targeted mosaic testing. If prior testing was performed at GeneDx, provide accession number and/or relative’s full name. If testing was performed at another lab or in research, a copy of the report and, when required, a positive control sample must be included. Upfront communication may be needed for certain scenarios (e.g., copy number variants not available, or genes/regions not amenable).

Limitations

Not available for copy number variants (CNVs). Some genes or gene regions may not be amenable to targeted mosaic variant testing. Turn‑around time may be extended due to external factors. Additional prior testing (e.g. trio, Xpanded panel) may require contact with GeneDx to assess utility.

Test Details