RAPID ANEUPLOIDY DETECTION
Massively parallel sequencing of cell-free, maternal plasma DNA was recently demonstrated to be a safe and effective screening method for fetal chromosomal aneuploidies. Here, we report an improved sequencing method achieving significantly increased throughput and decreased cost by replacing laborious sequencing library preparation steps with PCR employing a single primer pair. Using this approach, samples containing as little as 4% trisomy 21 DNA could be readily distinguished from euploid samples.
1 . (canceled)
2 . A method of detecting the presence or absence of aneuploidy, comprising:
a) contacting a sample comprising a nucleic acid from a human subject with a single primer pair, wherein said primer pair anneals to a plurality of repeat genomic regions present on a reference set of all twenty-two autosome human non-aneuploid chromosomes that would generate, during amplification, an expected distribution for said twenty-two autosome human non-aneuploid chromosomes,
wherein said nucleic acid comprises at least a portion of all twenty-two autosome chromosomes from said human subject;
b) amplifying at least a portion of said nucleic acid using the single primer pair, whereby a plurality of distinct amplicons are produced, wherein each of said amplicons in the plurality of distinct amplicons is less than 180 bp in length;
c) sequencing at least 3 nucleotides of each of the amplicons in the plurality of distinct amplicons;
d) aligning in silico the sequenced amplicons from each of said twenty-two autosome chromosomes from said human subject to said reference set of all twenty-two autosome human non-aneuploid chromosomes to produce a query distribution for each of said twenty-two autosome chromosomes from said human subject; and
e) identifying:
i) the presence or absence of aneuploidy by comparing said query distribution for at least one of said twenty-two autosome chromosomes from said human subject to said expected distribution for a corresponding at least one of said twenty-two autosome human non-aneuploid chromosomes.
3 . The method of claim 2 , wherein said sequencing at least 3 nucleotides of each of the amplicons comprises sequencing at least 5 nucleotides of each of the amplicons in the plurality of amplicons.
4 . The method of claim 2 , wherein said sequencing at least 3 nucleotides of each of the amplicons comprises sequencing at least 15 nucleotides of each of the amplicons in the plurality of amplicons.
5 . The method of claim 2 , wherein the presence of aneuploidy is identified in the sample.
6 . The method of claim 2 , wherein the absence of aneuploidy is identified in the sample.
7 . The method of claim 2 , wherein the average length of the plurality of amplicons is less than 150 bp.
8 . The method of claim 2 , wherein the sample is a blood sample, a plasma sample, a serum sample, a saliva sample, a tears sample, a sweat sample, a lymph sample, a urine sample, or a tissue sample.
9 . The method of claim 8 , wherein the sample is a maternal blood sample, a maternal plasma sample, or a maternal serum sample, and wherein the nucleic acid in said maternal blood sample, maternal plasma sample, or maternal serum sample comprises fetal chromosomes.
10 . The method of claim 2 , wherein unique sequence tags are incorporated at a 5′ end of the primers.
11 . The method of claim 2 , wherein, in step e), said at least one of said twenty-two autosome chromosomes from said human subject comprises all twenty-two autosome chromosomes from said human subject, and said corresponding at least one of said twenty-two autosome human non-aneuploid chromosomes comprises all twenty-two autosome human non-aneuploid chromosomes.
12 . The method of claim 2 , wherein the nucleic acid from said sample is not ligated to adapters.
13 . The method of claim 2 , wherein said query distribution comprises a normalized count of the number of sequenced amplicons at each position where they align to said reference set of said twenty-two autosome human non-aneuploid chromosomes.
14 . The method of claim 2 , wherein, in step e), said at least one of said twenty-two autosome chromosomes from said human subject comprises chromosomes 21, 13 and 18, and said corresponding at least one of said twenty-two autosome human non-aneuploid chromosomes comprises chromosomes 21, 13, and 18.
15 . The method of claim 2 , wherein said plurality of amplicons comprise at least 18,484 non-identical amplicons.