Mito Genome Sequencing & Deletion Testing

Casandra

Casandra Test Code GE83121Version 1 (DRAFT)

Performing Lab

Lab GeneDxLab Test ID 554

Mito Genome Sequencing & Deletion Testing

Clinical Use

Use

This clinical test is intended to aid in the diagnosis of suspected primary mitochondrial disorders by performing full‑sequence analysis of the mitochondrial genome plus testing for mitochondrial DNA deletions. It is expected to detect greater than 98 % of known pathogenic variants and deletions in the mitochondrial genome, and identifies a mitochondrial DNA variant in approximately 40 % of adults and 10–20 % of pediatric patients.

Special Instructions

If a maternal sample is provided at the same time as the proband specimen, sequence variants identified in the proband can be evaluated in the maternal sample via Sanger sequencing of the relevant mitochondrial genome regions.

Limitations

NGS may not detect large‐scale mtDNA deletions present at 5 % heteroplasmy or lower, or point variants present at 2 % heteroplasmy or lower. Sensitivity may be reduced for indels in repetitive regions. Sanger sequencing (for maternal confirmation) may fail to detect mutant heteroplasmy at levels ≤ 25 %. Variants of uncertain significance present below 10 % heteroplasmy are not reported. Likely benign and benign variants are not routinely reported but available upon request.

Test Details