Following a lengthy discovery period, the lab is asking a South Carolina federal district court to find in its favor and decide that its negligence did not result in the death of Williams' son.
In seven years, the public variant classification database has steadily become a resource that labs are submitting to and that genetics experts are consulting.
The firm hopes to return fewer VUS in its test reports and to accelerate the resolution of uncertain results issued to patients in that past.
The clinical genome-wide DNA methylation test can diagnose genetic diseases that are missed by exome or genome sequencing and evaluate variants of unknown significance.
The development is a positive for plaintiff Amy Williams, who has said she hopes her lawsuit will spur greater accountability and transparency among genetic testing labs.
Though the South Carolina Supreme Court said Quest was a healthcare provider, Williams can try to keep her case alive by arguing she's alleging ordinary negligence.
A study of more than 5,000 breast cancer patients found that multi-gene sequencing has rapidly replaced BRCA1/2-only tests, resulting in better pathogenic variant detection but also higher VUS rates.
The court's determination is critical to deciding if Williams v Quest/Athena can advance or if it must be dismissed on statute of repose grounds.
The clinicals labs contributing to the database are adding more case-level data and focusing on outlier interpretations.
Elisha Cooke-Moore, from a small town in Oregon, claims her doctors never showed her the test report or offered her genetic counseling to explain the results.