Hoping to have a safe genetic check

This study by scientists can provide a blood test without surgery to detect the genetic abnormalities of the uterus such as Down syndrome.

Existing unrelated tests - such as ultrasound - are very limited and tests need to be used for surgery to create a danger to pregnancy.This new technique is effective when examining fetal DNA samples in the mother's blood for very small variations in the genetic material sequence. The American Ravgen Group's work is detailed online in the Lancet Medical Journal of the United Kingdom. Experts say other methods may also yield good results.

Being able to identify genetic abnormalities at an early stage not only gives parents the opportunity to decide whether to continue to retain the fetus but also make the medical team consider to the need to monitor closely from the beginning until birth. Analysis of fetal DNA samples from mother's blood is possible at some time. However, its effectiveness is still limited because only a very small amount of 'pathway' DNA enters the mother's blood.

Characteristic model

The test can detect genetic abnormalities in the uterus.(Photo: BBC)

Ravgen's team led by Ravinder Dhallan was able to maximize the amount of DNA that could be recovered by treating blood samples with a chemical called formaldehyde (an aldehyde derivative of formic acid for sterilization).

Researchers took blood samples from 60 pregnant women. They then examined the genetic material to find mutations known as mutations of the DNA sequence (abbreviated as SNPs) when different from one nucleotide (a chemical compound consisting of another ring, sugar and one or more compounds). phosphate group). Because each chromosome has a specific SNPs model, researchers can distinguish the mother's and fetal DNA. They can also determine whether the fetus carries more major chromosomal simulations that cause genetic disease. For example, bring a chromosome simulation 21 that causes Down syndrome (gene disorder 21).

Of the 60 samples tested, this technique has correctly identified the number of chromosomes in 58 samples, including two cases of 21 gene disorders. One case of genetic disorder 21 was not recognized and a normal one. wrongly identified as a genetic disorder 21. However, the researchers stressed that their study was only at an early stage and more experiments needed to correct this approach. complete.

New era

Variation of DNA sequence (abbreviated as SNPs) when different from one nucleotide (Photo: emedicine.com)

Written in Lancet, Alexandra Benachi and Jean-Marc Costa, of Paris-Descartes University, said the experiment was promising and "opened a new era in prenatal testing". However, they added: 'Some technical issues still need to be overcome. First, the amount of fetal free DNA in maternal blood is very low, and although the use of formaldehyde allows a large amount to be separated from the mother's blood, the amount of DNA is not regular. Second, Dhallan estimates that just eight women in the first three months - more testing during this pregnancy will be very important. '

Dr. Lyn Chitty, an expert on genetics and fetal medicine at the University Hospital of London, said researchers are studying other ways to develop an unused test. dissect. These methods include testing proteins in mother's blood and epigenetics - studying spontaneous changes to fetal DNA. The doctor said: 'Most people think that one of these techniques will eventually improve enough to be useful in clinical applications. An accurate examination without surgery will mean that many women with normal babies do not have to undergo an amniocentesis through the abdomen. '

Professor Maj Hulten of Warwick University discovered a European Union research system to study new prenatal checkups. Professor said this study is very interesting especially for the treatment of formaldehyde blood samples and with further improvement, a non-surgical examination may soon become a reality. 'I would be surprised if this method alone turned out to be the method of winning the competition to become clinically useful.'

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