Patent ID: 7645576

Claim:
A method for detecting the presence of a chromosomal disorder in the fetus of a pregnant woman, comprising the steps of: (a) obtaining an RNA-containing biological sample from the pregnant woman, wherein the RNA-containing biological sample contains fetal RNA, and wherein the biological sample is selected from the group consisting of maternal blood, maternal plasma or serum, placental tissue, and a sample obtained via chorionic villus sampling (CVS); (b) discriminating alleles from RNA transcribed from at least one genetic locus from at least one chromosome of concern; (c) determining the ratio of the alleles of the RNA transcripts; and (d) comparing the ratio from step (c) to a standard control representing a ratio of alleles from comparable biological samples obtained from pregnant women each carrying a chromosomally normal fetus, wherein an increase or decrease in the ratio from the standard control indicates an increased risk of having a fetus with a chromosomal disorder.