Prenatal testing is a must-have for pregnant women, and screening for Down's syndrome is especially important for older women. The non-invasive prenatal genetic testing, which is now very common, entered China in 2010. So far, millions of women (both Huada and Berry and Kang have exceeded 1 million) have benefited from tens of thousands. The family has thus got rid of the heavy economic and psychological burden. However, this seemingly ordinary technology has an unusual experience.
To say non-invasive prenatal testing, it is of course to mention Sequenom, which was recently acquired by LabCorp (Laboratory Corporation of America) for $371 million. Sequenom is well known in the industry, after all, it is the first company in the US to offer commercial non-invasive prenatal genetic testing.
Speaking of the application of a wide range of non-invasive prenatal testing techniques, thanks to our Chinese scientists. In 1997, Professor Lu Yuming of the Chinese University of Hong Kong published an article in The Lancet. He found that during pregnancy, the fetus in the body releases DNA and RNA into the mother's plasma, accounting for about 5%. It can be said to open the door to non-invasive prenatal diagnosis.
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Professor Lu Yuming
After a lapse of 13 years, Professor Lu Yuming once again improved the technique and obtained a genome-wide map of the fetus in the peripheral plasma of pregnant women. This result means that in addition to some simple monogenic genetic diseases (such as red-green blindness), complex genetic diseases (Down's syndrome) can also be detected. This discovery successfully promotes non-invasive prenatal testing techniques. The world.
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To say that non-invasive prenatal testing, the corresponding "invasive" is amniocentesis. Amniocentesis is between 16-24 weeks of gestation. Under the guidance of B-ultrasound, a slender needle is used to pass through the belly and uterine wall of the pregnant woman, and 20 ml of amniotic fluid is taken from the amniocente. The most worrying aspect of this technology is that it may cause abortion in pregnant women, and the non-invasive prenatal testing is non-invasive because it takes the venous blood of pregnant women and does not pose a threat to the fetus. It is generally believed that non-invasive detection is more challenging in screening Down's syndrome because a small percentage of the DNA detected in the mother's blood comes from the fetus, and it is difficult to determine which DNA belongs to whom. It is also a point we need to overcome technically.
According to Professor Lu, about 5% of the mother's blood drawn from the fetus. Then, assuming that each milliliter of blood sample is equivalent to 1000 genomes, it contains a total of 1900 mother chromosome 21, 100 euploid fetal chromosome 21 or 150 21 trisomy 21 chromosome. If the diagnosing doctor finds a difference in 50 chromosomes in the DNA sample, he needs to count hundreds of thousands of molecules to improve the discriminating ability.
Xi'an XJeson Biotech Co., Ltd , https://www.xjesonbio.com