Guardant Health, Inc.
METHODS AND SYSTEMS FOR DETECTING ALLELIC IMBALANCE IN CELL-FREE NUCLEIC ACID SAMPLES

Abstract:

The present disclosure provides methods and systems for detecting an allelic imbalance in a sample from a subject, comprising: (a) sequencing cell-free DNA molecules from the sample to generate sequence reads; (b) aligning at least a portion of the sequence reads to a reference sequence to produce aligned sequence reads; (c) for at least a portion of the plurality of aligned sequence reads, identifying a germline variant present at a mutant allele fraction (MAF) in the sample, thereby identifying a set of germline variants in the sample, wherein individual germline variants in the set of germline variants have corresponding MAF values; (d) determining a quantitative measure of the set of germline variants that are among a plurality of discrete ranges of MAF values; and (e) detecting the allelic imbalance based on a predetermined criterion by filtering the set of germline variants based on at least the quantitative measure.