Patent Document ID: 9982300
Application ID: 14089720
Patent Flag: 1

Claim One:
1. A method for performing prenatal diagnosis of a sequence imbalance in a biological sample obtained from a female subject pregnant with a fetus, wherein the biological sample includes a mixture of cell-free DNA molecules that are part of DNA sequences of a human genome, the biological sample including DNA molecules from the fetus and the female subject, the method comprising: extracting the mixture of cell-free DNA to obtain the biological sample; for each of a plurality of the DNA molecules in the biological sample: measuring a size of the DNA molecule, wherein measuring the size of the DNA molecule comprises: paired-end sequencing of the DNA molecule to obtain two sequence reads, wherein the paired-end sequencing is part of performing a random sequencing of the plurality of DNA molecules in the biological sample, and identifying which nucleic acid sequence in the human genome the DNA molecule is derived from, wherein identifying which DNA sequence the DNA molecule is derived from includes: aligning, by a computer system, the two sequence reads to the human genome; calculating, by the computer system, a first statistical value from the sizes of DNA molecules from a first sequence; identifying one or more reference sequences; calculating, by the computer system, a second statistical value from the sizes of DNA molecules from the one or more reference sequences; determining a parameter using the first statistical value and the second statistical value, the parameter being a difference or a ratio of the first statistical value and the second statistical value; and determining a classification of whether a sequence imbalance exists for the first sequence based on a comparison of the parameter to a cutoff value.