Fetus chromosome detecting system based on DNA variation counting

Abstract

The invention provides a fetus chromosome detecting method based on DNA variation counting. The method comprises the steps of obtaining and sequencing free DNA of plasma in a peripheral blood sample of a pregnant woman, comparing the free DNA of the plasma with human reference sequences, namely DNA long sequences on 24 chromosomes, counting the number of variation in the free DNA of the plasma andconducting comparison. The invention further discloses a system for achieving the detecting method. The system comprises a DNA short sequence data input module, a module for positioning short sequences on the long sequences, a module for founding sequence difference, a difference screening module, a first counting module and a second counting module, wherein the modules are sequentially and electrically connected. According to the fetus chromosome detecting method based on DNA variation counting and the system for achieving the method, by detecting chromosomes in peripheral blood of the pregnant woman, whether there is chromosome abnormality or not in a fetus is judged, thus harmful effects on the pregnant woman and the fetus in a detecting process are greatly reduced, and by calculatingthe variation number to judge the chromosome abnormality of the fetus, compared with a method that a sequence number is calculated simply, the fetus chromosome detecting method based on DNA variationcounting is more accurate.

Description

technical field [0001] The invention relates to the field of medical detection, in particular to a non-invasive prenatal biological information detection system. Background technique [0002] The incidence of 21, 13, and 18 chromosome aneuploid fetuses is about 1 / 500. Children with these diseases will bring a heavy burden to the family and society in the future. At present, non-invasive prenatal detection technology has been applied and promoted, and the accuracy is as high as 99.9%, most of the fetuses with chromosomal aneuploidy can be detected. However, according to the "China Birth Defect Prevention Report 2012" issued by the Ministry of Health, the incidence of birth defects in my country is close to the average level of the world's medium-importing countries, about 5.6%, and the number of new birth defects is about 900,000 cases every year. Visible birth defects accounted for about 250,000 cases, accounting for about 1.5% of babies, and 19.1% of infant deaths were dire...

AI Technical Summary

Problems solved by technology

Because the selection of DNA fragments in the previous method is completely random and the coverage depth is low, for a specific region on the chromosome, there is no guarantee that DNA fragments will be detected and there will be enough DNA fragments for subsequent analysis, so this method cannot accurately detect small fragments. Chromosomal abnormalities

[0005] A disadvantage of this method is that the detection accuracy is not enough

When the proportion of DNA fragments from the fetus is relatively small (eg, less than 2%), the detection of chromosome 3 may miss detection (false negative)

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