Sequencing methods and compositions for prenatal diagnoses
AssigneeVerinata Health, Inc.
InventorsRichard P. Rava, Manjula Chinnappa, David A. Comstock, Gabrielle Heilek, Brian Kent Rhees
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Abstract
The invention provides methods for determining aneuploidy and/or fetal fraction in maternal samples comprising fetal and maternal cfDNA by massively parallel sequencing. The method comprises a novel protocol for preparing sequencing libraries that unexpectedly improves the quality of library DNA while expediting the process of analysis of samples for prenatal diagnoses.
Claims11
A method for determining a fetal chromosomal aneuploidy in a maternal sample comprising a mixture of fetal and maternal nucleic acids molecules, said method comprising:
- (a) preparing a sequencing library from said mixture of fetal and maternal nucleic acid molecules;
- wherein preparing said library comprises the consecutive steps of end-repairing, dA-tailing and adaptor ligating said nucleic acids;
- (b) sequencing at least a portion of said nucleic acid molecules, thereby obtaining sequence information for a plurality of fetal and maternal nucleic acid molecules of a maternal sample;
- (c) using the sequence information to obtain a chromosome dose for an aneuploid chromosome;
- and
- (d) comparing said chromosome dose to at least one threshold value, and thereby identifying the presence or absence of fetal aneuploidy
2-43. (canceled)
A method for preparing a sequencing library from a test sample comprising nucleic acid molecules, wherein said nucleic acids are human cell-free DNA (cfDNA) molecules, wherein the method comprises the consecutive steps of end-repairing, dA-tailing and adaptor ligating said nucleic acids, wherein said consecutive steps exclude purifying the end-repaired products prior to the dA-tailing step and exclude purifying the dA-tailing products prior to the adaptor-ligating step, and wherein said consecutive steps are performed in less than 1 hour.
Dependencies are inferred from the claim text.