The comment period for the FDA draft guidance addressing the use of public gene-variant databases to support clinical validity for next-generation sequencing (NGS) systems is closed, but at least one stakeholder sees a major point of ambiguity that could stymie regulatory review of these high-volume DNA tests. San Diego-based Illumina Inc. said in its comments to the docket that the draft fails to spell out what sort of role these databases will play, speculating that they could serve as anything from industry-wide standards to special controls for specific tests, a difference that could have important implications for premarket review.