Mitochondrial Whole Genome Sequence Analysis (Familial Mutation/Variant Analysis)

Clinical Use

Use

The Mitochondrial Whole Genome Sequence Analysis (Familial Mutation/Variant Analysis) focuses on sequencing the mitochondrial region to identify known familial variants. It is essential for patients with a family history of mitochondrial diseases or known mitochondrial variants, particularly when planning pregnancies or for symptomatic individuals. The test contributes to understanding mitochondrial inheritance, which is maternal and denotes that these disorders can be inherited from mothers to children. The analysis aids in confirming diagnoses and informing carrier screening for prospective parents. Comprehensive details regarding the patient’s relationship to the tested relative and their clinical status must accompany the specimen submission to ensure accurate interpretation of results.

Special Instructions

This test necessitates prior discussion with a genetic counselor if the familial variant was identified in another laboratory. Furthermore, it's important to note that Sanger sequence analysis does not detect low-level mutant heteroplasmy or provide quantification; for this purpose, test code 2056 should be ordered.

Limitations

Sanger sequencing is limited in its ability to detect low-level heteroplasmy; thus, its sensitivity might overlook mutations present at less than a certain threshold. This can lead to false-negative results in cases of complex mitochondrial inheritance where heteroplasmy varies among tissues. Further, interpretation of the correlation between detected mutations and clinical outcome relies heavily on the prior identification of familial variants. If not previously documented, the value of the test may be compromised. Some specimens may also degrade or become unsuitable for testing if not handled or stored following defined protocols, impacting the validity of the findings.

Test Details