Whole Exome Sequencing for Hereditary Disorders, Varies

Casandra

Casandra Test Code MC54952Version 1 (DRAFT)

Performing Lab

Lab Mayo Clinic LabLab Test ID WESDXCPT Code 81415

Whole Exome Sequencing for Hereditary Disorders, Varies

Clinical Use

Use

This test serves as a first-tier diagnostic tool to identify molecular diagnoses in patients with suspected genetic disorders. It aids in understanding natural history and prognosis, targeted management, predictive testing of at-risk family members, and recurrence risk assessment. It is also used as a second-tier test for patients where previous genetic testing was negative, offering a potentially cost-effective alternative to multiple independent assays.

Special Instructions

This test requires specific paperwork to proceed. Complete the Whole Exome Sequencing: Ordering Checklist and submit it with the specimens. For family member specimens as comparators, order CMPRE / Family Member Comparator Specimen for Exome Sequencing, Varies. Ensure specimens from the proband, biological mother, and father are submitted for trio analysis when possible. Prior authorization is available but not required.

Limitations

Whole exome sequencing cannot detect deep intronic variants, trinucleotide repeat variants, or variants in the mitochondrial genome. It is not designed for identification of somatic variants in solid tumors or for pharmacogenomic genotyping. Technical limitations may prevent detection in regions with homology, high GC content, and repetitive sequences. The sensitivity for detecting deletions and insertions is greater than 95% for certain sizes, but some copy number and structural variants may not be reliably detected.

Test Details

New York Approved

Methodology

NGS (Targeted)

Biomarkers

Sequence Capture and Targeted Next-Generation Sequencing (NGS) followed by Sanger Sequencing or Quantitative PCR (qPCR), as needed, covering the protein-coding regions of about 20,000 genes.

No genes

Gene

SNV/Indel • Mutation • Categorical (e.g., Positive / Negative / Indeterminate)