Natera, Inc.

The invention provides methods, systems, and computer readable medium for detecting ploidy of chromosome segments or entire chromosomes, for detecting single nucleotide variants and for detecting both ploidy of chromosome segments and single nucleotide variants. In some aspects, the invention provides methods, systems, and computer readable medium for detecting cancer or a chromosomal abnormality in a gestating fetus.

The invention provides methods for simultaneously amplifying multiple nucleic acid regions of interest in one reaction volume as well as methods for selecting a library of primers for use in such amplification methods. The invention also provides library of primers with desirable characteristics, such as minimal formation of amplified primer dimers or other non-target amplicons.

The disclosure herein provides methods and compositions for detecting or monitoring immune cell populations in biological samples. The methods and compositions disclosed herein are particularly useful for detecting or monitoring immune cell populations in patients suffering from a disease or undergoing treatment of a disease resulting in depletion of immune cells. In particular, the present disclosure provides method for using multiplex PCR combined with next-generation DNA sequencing to detect DNA containing recombined V(D)J gene segments which can be used to detect immune cells.

The invention provides methods for simultaneously amplifying multiple nucleic acid regions of interest in one reaction volume as well as methods for selecting a library of primers for use in such amplification methods. The invention also provides library of primers with desirable characteristics, such as minimal formation of amplified primer dimers or other non-target amplicons.

Provided herein are materials and methods relating to cell-free DNA. In particular, the technology relates to methods and materials for the preparation and handling of blood samples for future use in applications involving cell-free DNA.

The invention provides methods for simultaneously amplifying multiple nucleic acid regions of interest in one reaction volume as well as methods for selecting a library of primers for use in such amplification methods. The invention also provides library of primers with desirable characteristics, such as minimal formation of amplified primer dimers or other non-target amplicons.

The present disclosure provides methods for determining the ploidy status of a chromosome in a gestating fetus from genotypic data measured from a mixed sample of DNA comprising DNA from both the mother of the fetus and from the fetus, and optionally from genotypic data from the mother and father. The ploidy state is determined by using a joint distribution model to create a plurality of expected allele distributions for different possible fetal ploidy states given the parental genotypic data, and comparing the expected allelic distributions to the pattern of measured allelic distributions measured in the mixed sample, and choosing the ploidy state whose expected allelic distribution pattern most closely matches the observed allelic distribution pattern. The mixed sample of DNA may be preferentially enriched at a plurality of polymorphic loci in a way that minimizes the allelic bias, for example using massively multiplexed targeted PCR.

The invention provides methods for preparing a preparation of amplified DNA derived from a biological sample of a patient who has been diagnosed with cancer useful for determining relapse or metastasis of cancer, comprising (a) sequencing DNA isolated from hematopoiesis cells in a blood or bone marrow sample of the patient or a fraction thereof to determine the presence or absence of one or more clonal hematopoiesis of indeterminate potential (CHIP) mutations; (b) sequencing (i) DNA isolated from a tumor biopsy sample of the patient or (ii) cell-free DNA isolated from the blood or bone marrow sample or a fraction thereof, to identify a plurality of patient-specific somatic mutations associated with the cancer; (c) preparing a preparation of amplified DNA by performing targeted multiplex amplification on cell-free DNA isolated from a longitudinally collected biological sample of the patient or a fraction thereof to amply a plurality of target loci to obtain amplified DNA, wherein each of the target loci spans a patient-specific somatic mutation identified in step (b) and does not span any CHIP mutation identified in step (a), wherein the biological sample is a blood, urine, or bone marrow sample; and (d) analyzing the preparation of amplified DNA by sequencing the amplified DNA to determine the presence or absence of the patient-specific somatic mutations, wherein the presence of two or more patient-specific somatic mutations associated with the cancer and the presence of one or more CHIP mutations are indicative of relapse or metastasis of the cancer.

Provided herein are improved methods for detecting aneuploidy in a sample. The methods in certain embodiments are used for the analysis of circulating DNA in serum samples, such as circulating fetal DNA or circulating tumor DNA. In certain embodiments, chromosome or chromosome segments of interest are used to set a bias model and/or a control value for a z-score determination, in illustrative examples without the use of a control chromosome.

Disclosed here is a method for detecting genome rearrangement in a biological sample, comprising: obtaining a contact matrix plotted from proximity ligation sequencing data of at least one chromosome; identifying an abnormal contact pattern in the contact matrix compared to the contact matrix of a reference genome; comparing the abnormal contact pattern in the contact matrix to one or more known patterns associated with genomic rearrangement to identify a type of genomic rearrangement causing the abnormal contact pattern. Also disclosed is a method for detecting genome rearrangement in a biological sample, comprising: selecting linked chromosomal fragments from proximity ligation sequencing data of at least one chromosome, identifying an abnormal covalent bonding pattern of the linked chromosomal fragments compared to a reference genome; and comparing the abnormal covalent bonding pattern to one or more known patterns associated with genomic rearrangement to identify genomic rearrangement causing the abnormal covalent bonding pattern.