Whole Exome Sequencing – Proband Only, Products of Conception (POC)

Amniotic fluid, chorionic villus sample (CVS), cultured amniocytes, cultured villi or fetal tissue/product of conception (POC). Cultured cells are required for testing. A direct specimen can be submitted, but a culture fee may be included.

10-15 mL amniotic fluid, 25 mg CVS, >2 to 4 mm(3) fetal tissue or two T-25 flasks of cultured amniocytes or cultured villi, preferably ~90% confluent. TAT will be extended by 7-14 days if cells are not confluent upon arrival.

5 mL amniotic fluid, 10 mg CVS, 2mm(3) fetal tissue, or two T-25 flasks cultured amniocytes or cultured villi

Sterile plastic conical tube or two T-25 flasks. For fetal tissue samples: Sterile container with sterile Ringer's lactate or Hanks' balanced salt solution or transport medium provided by cytogenetics laboratory. Do not use urine containers for shipping.

• Room temperature: 2 - 3 days

• Refrigerated: 2 - 3 days

• Frozen: Do not freeze.

WES is currently intended for use by patients suspected to have a genetic disorder. While the test is most frequently ordered for patients who have been unable to obtain a definitive diagnosis through traditional genetic testing, physicians may opt to initiate whole exome sequencing earlier in the diagnostic pathway. An initial workup using whole exome sequencing may be especially useful when a multigene testing approach is desired but would be prohibitively time-consuming, or when a known genetic disorder is suspected but testing for the genes of interest is not available. Patients with atypical presentation of a suspected syndrome may be candidates for exome sequencing. While patients can be of any age, many of the patients with the most pressing need for exome-wide interpretation are children with serious childhood genetic diseases. 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.

The scientific knowledge of the genome is incomplete and the technical ability to capture quality sequence data varies across the genome. A negative result does not exclude a genetic basis for the patient's condition. This assay is able to detect some mitochondrial DNA (mtDNA) variants. However, certain mtDNA variants, such as low level heteroplasmic variants, pathogenic mtDNA variants known to be undetectable in blood, large mtDNA deletions, and mtDNA depletion, are not detectable by this assay. If WES test results are negative and an mtDNA-related disease is suspected, mtDNA testing using a mitochondrial specific testing platform should be considered. This test is not intended to detect mosaicism, copy number variations, trinucleotide repeat expansions or epigenetic effects. It may not detect large chromosomal rearrangements, variants in regions with highly repetitive elements, regions with very high similarity to other regions, regions with insufficient coverage, or regions outside targeted regions, such as non-coding or regulatory regions. Sensitivity for detection of insertions and deletions may be lower than for base substitutions. While whole exome may confirm a diagnosis, findings may not impact patient management, including therapeutic options, or improve patient outcomes.

This test was developed and its performance characteristics determined by Labcorp. It has not been cleared or approved by the Food and Drug Administration.

Whole Exome Sequencing