A method for increasing the proportion of fetal free DNA in the plasma free DNA sequencing library of pregnant women

Abstract

The invention discloses a method for improving a proportion of fetal free DNA in a maternal plasma free DNA sequencing library. The method comprises the following steps: extracting maternal plasma free DNA; adding specific sequence tags at two ends of the maternal plasma free DNA so as to obtain plasma free DNA with maternal individual identification markings; subjecting the plasma free DNA with the maternal individual identification markings to PCR amplification so as to obtain an original library of maternal individual plasma free DNA; and recovering the maternal original library in a selected length range so as to obtain a recovered library used for high-throughput sequencing, or mixing the maternal original libraries of a plurality of different individual pregnant women so as to build the recovered library. The method provided by the invention can accurately detect a sample with excessively low content of maternal peripheral plasma fetal free DNA, reduces the sequencing data volume of every sample, improves the sample throughput of a sequencing reaction, reduces detection cost, and facilitates large-scale popularization.

Description

technical field [0001] The invention relates to the field of biotechnology genetic engineering. More specifically, it relates to a method for increasing the proportion of fetal cell-free DNA in a maternal plasma cell-free DNA sequencing library. Background technique [0002] Chromosomal aneuploidy refers to the increase or decrease in the number of one or several chromosomes in a cell compared to the normal 46 chromosomes in a human being. Changes in the number of chromosomes, especially aneuploidy, are closely related to some human diseases and also to Significant morbidity and mortality in infancy are closely related. These disorders increase with maternal age. According to literature reports, about 100,000 newborns with chromosomal abnormalities are born in China every year. Among live births, chromosomal abnormalities account for 0.3%. Chromosomal abnormalities are the main cause of a large number of birth defects. The abnormality mainly refers to the number or struct...

AI Technical Summary

Problems solved by technology

At present, the samples of non-invasive prenatal testing are all plasma cell-free DNA of pregnant women, but there are a large amount of maternal cell-free DNA in the cell-free DNA, and the content of fetal cell-free DNA varies greatly due to individual differences, and the content of fetal cell-free DNA in some samples is too low, resulting in accurate Reduced reliability, low sequencing throughput, and high detection costs

The ACOG guidelines emphasize that due to individual reasons, the fetal free DNA content may be too low, and the test results cannot be obtained. At this time, the possibility of repeated testing to obtain accurate results is only 50–60%. Therefore, when the fetal free DNA content is too low , the accuracy of non-invasive prenatal testing results is also relatively reduced

In order to ensure the accuracy of each sample detection, the current common practice is to increase the amount of sample detection data, thereby reducing the sample size of each sequencing run, resulting in relatively high detection costs.

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