The Chinese University of Hong Kong

Sequenom, Inc.

Wai Kwun Rossa Chiu

Yuk Ming Dennis Lo

Kwan Chee Chan

Wenli Zheng

Peiyong Jiang

Jiawei Liao

Chunming Ding

Charles Cantor

Bo Yin Tsui

Yuk-Ming Dennis Lo

Stephen Siu Chung Chim

Cheuk Yin Jandy Yu

Stephen Siu-Chung Chim

Nancy Bo Yin Tsui

Yu-Kwan Tong

Yu Kwan Tong

Kai On Ng

Siu Chung Stephen Chim

Kwok Pui Fung

Tak Yeung Leung

Zhang Chen

Kwok Wing Tsui

Mary Miu Yee Waye

Siu Lun John Tam

Kay Sheung Paul Chan

Hao Sun

The present invention relates to new methods for diagnosing a pregnancy-associated disorder by analyzing fetal DNA present in the mother's blood. More specifically, this invention relies on the discovery that the maspin gene is differentially methylated in fetal DNA and in maternal DNA and provides these new diagnostic methods, which distinguish fetal DNA from maternal DNA and detect prenatal disorders based on abnormalities in fetal DNA level and methylation status.

Marker for prenatal diagnosis and monitoring

Systems and methods for identifying a de novo mutation in a genome of a fetus are provided. Methods may include identifying a location of each of a plurality of cell-free nucleic acid molecules using sequence reads. Methods may also include identifying a first sequence in the sequence reads at a first location that is not present in the maternal or paternal sequences. Methods may additionally include determining a first fractional concentration of the first sequence in the biological sample at the first location. Further, methods may include determining a second fractional concentration of a fetal-specific second sequence. The second sequence may be inherited by the fetus from the father at the second location. In addition, methods may include classifying the first sequence as a de novo mutation at the first location in a fetal genome of the fetus if the first and second fractional concentrations are about the same.

Identifying a de novo fetal mutation from a maternal biological sample

Systems, methods, and apparatuses for performing a prenatal diagnosis of a sequence imbalance are provided. A shift (e.g. to a smaller size distribution) can signify an imbalance in certain circumstances. For example, a size distribution of fragments of nucleic acids from an at-risk chromosome can be used to determine a fetal chromosomal aneuploidy. A size ranking of different chromosomes can be used to determine changes of a rank of an at-risk chromosome from an expected ranking. Also, a difference between a statistical size value for one chromosome can be compared to a statistical size value of another chromosome to identify a significant shift in size. A genotype and haplotype of the fetus may also be determined using a size distribution to determine whether a sequence imbalance occurs in a maternal sample relative to a genotypes or haplotype of the mother, thereby providing a genotype or haplotype of the fetus.

Size-based genomic analysis

A fractional concentration of clinically-relevant DNA in a mixture of DNA from a biological sample is determined based on amounts of DNA fragments at multiple sizes. For example, the fractional concentration of fetal DNA in maternal plasma or tumor DNA in a patient's plasma can be determined. The size of DNA fragments in a sample is shown to be correlated with a proportion of fetal DNA and a proportion of tumor DNA, respectively. Calibration data points (e.g., as a calibration function) indicate a correspondence between values of a size parameter and the fractional concentration of the clinically-relevant DNA. For a given sample, a first value of a size parameter can be determined from the sizes of DNA fragments in a sample. A comparison of the first value to the calibration data points can provide the estimate of the fractional concentration of the clinically-relevant DNA.

Size-based analysis of fetal DNA fraction in plasma

A classification of a level of cancer in an organism is determined by analyzing a biological sample of the organism. The biological sample comprises clinically-relevant DNA and other DNA. At least some of the DNA is cell-free in the biological sample. An amount of a first set of DNA fragments from the biological sample corresponding to each of a plurality of sizes is measured. A first value of a first parameter is calculated based on the amounts of DNA fragments at the plurality of sizes. The first value is compared to a reference value. A classification of a level of cancer in the organism is determined based on the comparison.

Size-based sequencing analysis of cell-free tumor DNA for classifying level of cancer

Size-based analysis of cell-free tumor DNA for classifying level of cancer

Whether a fetus has an aneuploidy associated with a first chromosome is detected using ratios of alleles detected in a maternal sample having a mixture of maternal and fetal DNA. DNA from the sample is enriched for target regions associated with polymorphic loci and then sequenced. Polymorphic loci (e.g., single nucleotide polymorphisms) in the target regions with fetal-specific alleles are identified on a first chromosome and on one or more reference chromosomes. A first ratio of the fetal-specific alleles and shared alleles is determined for the loci on the first chromosome. A second ratio of the fetal-specific alleles and shared alleles is determined for the loci on the reference chromosome(s). A third ratio of the first and second ratio can be compared to a cutoff to determine whether an aneuploidy is present, and whether the aneuploidy is maternally-derived or paternally-derived.

Noninvasive prenatal diagnosis of fetal trisomy by allelic ratio analysis using targeted massively parallel sequencing

Disclosed herein are methods and kits for selectively amplifying, detecting or quantifying a DNA fragment with a specific end sequence, especially generated following restriction enzyme digestion. This method can be used, for example, to detect a hypomethylated DNA fragment. This methods and kits are especially useful in detecting or quantifying a hypomethylated fetal DNA fragment in a maternal plasma sample containing a corresponding hypermethylated maternal DNA fragment.

Methods and kits for selectively amplifying, detecting or quantifying target DNA with specific end sequences

Classification of cancer level based on genomic coordinates of outermost nucleotides of cell-free DNA

Methods, apparatuses, and system are provided for analyzing a maternal sample to determine whether a male fetus of a pregnant female has inherited an X-linked mutation from the mother. A percentage of fetal DNA in the sample is obtained, and cutoff values for the two possibilities (fetus inherits mutant or normal allele) are determined. A proportion of mutant alleles relative to a normal allele on the X-chromosome can then be compared to the cutoff values to make a classification of which allele is inherited. Alternatively, a number of alleles from a target region on the X-chromosome can be compared to a number of alleles from a reference region on the X-chromosome to identify a deletion or amplification. The fetal DNA percentage can be computed by counting reactions with a fetal-specific allele, and correcting the number to account for a statistical distribution among the reactions.

Noninvasive prenatal genotyping of fetal sex chromosomes

Techniques are provided for determining inheritance of maternal and paternal haplotypes in preganncies with multiple fetuses. Maternal inheritance can be determined at loci where the mother is heterozygous and the paternally inherited alleles are known (e.g., the father is homozygous). Two types of loci may be used, where one type has the paternal allele appear on a first maternal haplotype, and another type has the paternal allele appear on a second maternal haplotype. Paternal inheritance can be determined from loci where the father is heterozygous and the maother is homozygous. Amounts of different alleles at each locus can be measured. A comparison of the amounts (e.g., using a fractional concentration of each allele and cutoffs) can be used to determine the haplotype inheritance. A haplotype can be linked to a condition of interest.

Determining fetal genomes for multiple fetus pregnancies

Size-based analysis of fetal or tumor DNA fraction in plasma

Systems, methods, and apparatus for determining at least a portion of fetal genome are provided. DNA fragments from a maternal sample (maternal and fetal DNA) can be analyzed to identify alleles at certain loci. The amounts of DNA fragments of the respective alleles at these loci can be analyzed together to determine relative amounts of the haplotypes for these loci and determine which haplotypes have been inherited from the parental genomes. Loci where the parents are a specific combination of homozygous and heterozygous can be analyzed to determine regions of the fetal genome. Reference haplotypes common in the population can be used along with the analysis of the DNA fragments of the maternal sample to determine the maternal and paternal genomes. Determination of mutations, a fractional fetal DNA concentration in a maternal sample, and a proportion of coverage of a sequencing of the maternal sample can also be provided.

Determination of the depth coverage of the fetal genome

Growing community of inventors

Shatin, China

Wai Kwun Rossa Chiu