Patent Document ID: 20140080720
Application ID: 14089720
Patent Flag: 0

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 nucleic acid molecules that are part of nucleic acid sequences, the biological sample including nucleic acid molecules from the fetus and the female subject, the method comprising: for each of a plurality of the nucleic acid molecules in the biological sample: measuring a size of the nucleic acid molecule, and identifying which nucleic acid sequence the nucleic acid molecule is derived from; calculating, by a computer system, a first statistical value from the sizes of nucleic acid molecules from a first sequence; identifying one or more reference sequences that have a GC content that is similar to a GC content of the first sequence; calculating, by the computer system, a second statistical value from the sizes of nucleic acid 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.