Whole Exome Sequencing - TRIO (Proband)

Casandra

Casandra Test Code LC73801Version 1 (DRAFT)

Performing Lab

Lab LabcorpLab Test ID 620022CPT Codes 81415, 81416

Whole Exome Sequencing - TRIO (Proband)

Clinical Use

Use

Whole Exome Sequencing (WES) is a genetic test used to identify a heritable cause of a disorder. WES searches through all coding regions of all genes currently identified; thus, it has a higher chance to find the cause of a heritable disease. WES can be used if a patient has symptoms, which, after exhaustive testing, cannot be linked to a diagnosis and corrective treatment is necessary to change the prognosis. WES can also be used if, upon clinical presentation, multiple disease states may be suspected and a clinician wishes to improve his/her testing approach. Once a genetic variant has been identified, this information can then be linked back to the phenotype of the patient, which will improve the pathway to a correct diagnosis and a suitable treatment plan can be administered. TRIO testing consists of a proband or patient sample, and both biological parents. In the case both parents are not available for testing, up to two family member samples are also accepted. TRIOs are preferred for better diagnostic sensitivity.

Special Instructions

Samples must be accompanied by both a consent form and a clinical questionnaire and/or supporting clinical documents or they will not be processed.

Limitations

This assay will not consistently detect mosaicism or rule out the presence of large chromosomal aberrations, including rearrangements and inversions that do not change copy number of genomic regions. The NGS assay does not detect repeat expansions. False positive or false negative results may occur due to various factors including insufficient information about rare genetic variants, sex chromosome abnormalities, pseudogene interference, homologous regions, blood transfusions, bone marrow transplantation, somatic or tissue-specific mosaicism/heteroplasmy, mislabeled samples, or erroneous representation of family relationships. For panels with mitochondrial DNA assessment, low levels of heteroplasmy may not be reliably detected. Interpretation of the clinical significance of gene variants is limited by available data at the time of reporting and the quality and completeness of provided clinical information. The interpretation of variant significance may change over time.

Test Details

Methodology

NGS (Targeted)

Biomarkers

This component uses next-generation sequencing to identify genetic variants across the exome, focusing on single nucleotide variants, insertions, deletions, and copy number variants.