| CPC G16B 20/10 (2019.02) [G16B 20/00 (2019.02); G16B 20/20 (2019.02); G16B 25/00 (2019.02); G16B 25/10 (2019.02); G16B 30/00 (2019.02); G16B 30/10 (2019.02); G16B 30/20 (2019.02)] | 8 Claims |
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1. A method comprising:
(a) sequencing circulating cell-free nucleic acid from a test sample from a pregnant subject bearing a fetus by targeted sequencing of chromosomes consisting of chromosome 13, chromosome 18, and chromosome 21, thereby generating sequence reads;
(b) mapping, using a microprocessor, the sequence reads to portions of a reference genome;
(c) counting, using a microprocessor, the sequence reads mapped to the portions;
(d) calculating, using a microprocessor, three ratios from the counts, wherein the three ratios comprise:
(i) a ratio between counts mapped to chromosome 13, or segment thereof, to counts mapped to chromosome 21, or segment thereof,
(ii) a ratio between counts mapped to chromosome 13, or segment thereof, to counts mapped to chromosome 18, or segment thereof, and
(iii) a ratio between counts mapped to chromosome 18, or segment thereof, to counts mapped to chromosome 21, or segment thereof;
(e) comparing the three ratios calculated in (d) with one or more corresponding ratios from one or more euploid reference samples to generate a comparison, wherein the comparing comprises plotting the three ratios calculated in (d) in three dimensions, which dimensions are the ratios, and the comparison is a point for the subject on a three-dimensional plot; and
(f) reporting, based on the comparison, a classification of a presence or absence of a chromosome aneuploidy for the test sample.
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