NONINVASIVE METHOD OF CALCULATING RISK OF FETAL SEX CHROMOSOMAL ANEUPLOIDY

摘要

To provide methods for non-invasive determination of Y chromosomal abnormalities indicating the aneuploidy in a maternal sample by detecting and determining the relative contribution of genetic sequences of the Y chromosome in the maternal sample.SOLUTION: A method according to the present invention comprises: calculating a fetal nucleic acid percentage in a maternal sample by investigating the genetic loci of a Y chromosome, investigating the polymorphic loci of a first autosome, and analyzing the frequency of the polymorphic loci of the first autosome; estimating a relative frequency of a fetal chromosome in the maternal sample with the Y chromosome and the first autosome; using the calculated fetal nucleic acid percentage to calculate the value of likelihood of the fetal Y chromosome being present in the maternal sample by 0 copy, 1 copy, or 2 or more copies; comparing the value of likelihood with a first mathematical model in which 0 copy of the fetal Y chromosome is assumed, a second mathematical model in which 1 copy of the Y chromosome is assumed, and a third mathematical model in which 2 or more copies of the Y chromosome are assumed to calculate the risk of fetal Y chromosomal aneuploidy in the maternal sample.SELECTED DRAWING: Figure 1