Genome check controversial in embryos

New genomic check-up in embryos can indicate illness or disability at an early stage

05/07/2012

Now that a research team has succeeded in deciphering the genome of an embryo from the mother's blood and the father's saliva, American scientists have now developed a test that requires only the mother's blood. While a risky amniotic fluid examination was previously required to detect, for example, trisomy 21 (Down syndrome), a blood test now seems sufficient. The new developments lead to heated discussions among politicians, ethicists, physicians and stakeholders.

For a new gene test, the blood of the mother is sufficient
Many future parents will breathe easy. So far, they have had to decide whether to have a risky amniocentesis test to diagnose a possible disease or disability in their unborn child, and soon a test will be on the market in Germany that only requires the mother's blood. But the new developments do not meet with approval everywhere. Physicians, ethicists, politicians and stakeholders discuss the necessity and consequences of such tests. As „Seal Online“ reports, the Federal Government's Disability Commissioner will present an expert opinion on this topic today.

After a research team led by Jacob O. Kitzman and Jay Shendure of the University of Washington in Seattle developed a test that required not only the mother's blood but also her father's saliva, Stanford University researchers managed a test without the genetic information of the father. Only by the blood of the mother they analyzed the genetic material of an embryo. Stephen Quake and Christina Fan from Stanford University report in the science magazine „Nature“, that their test is based on the DNA in the blood plasma of the mother, in which there is also a small part of the genetic material of the fetus. The researchers counted certain DNA sections on the chromosomes.

Previously, scientists from Stanford developed a test that analyzes fetal DNA snippets in the mother's blood to detect chromosome 21. If it occurs three times instead of just twice, the unborn child has Trisomy 21, also known as Down Syndrome. As „Seal Online“ reported, the PraenaTest will be brought in the coming days by the company Lifecodexx on the German market.

DNA test allows examination for many diseases before birth
Since the mother's blood also contains small amounts of the genetic material of the fetus, the scientists were able to draw conclusions about the entire genome of the unborn child. An embryo usually has two chromosomes of each type, so that each one of the father and mother will pass on one and is duplicated. A haplotype is a group of DNA patterns on a chromosome that is inherited together. Researchers hypothesized that the haplotypes inherited from the mother to the child are increasingly present in their blood, as they are present both in their own genetic material and in part in that of the embryo. The remaining genetic material must therefore either come from the father or be created by new mutations.

According to researchers, future life-threatening illnesses with medical complications in the first and second trimester of pregnancy could be determined by the test. Later, metabolic diseases could be diagnosed, whose treatment must begin immediately after birth. „We assume that there are no technical barriers and many practical applications to determine the entire fetal genome without invasive methods, "the researchers said.

In order to be able to carry out a genetic test on a fetus, an amniocentesis examination had to be carried out so far or a tissue sample of the suckling cake had to be taken. This can lead to a miscarriage in one in a hundred cases.

Critics fear selection of disabled babies
The new genetic tests provide plenty of fuel from an ethical and moral point of view. Critics fear that disabled babies will be sorted out in the future because of the genetic material. They assume that the number of abortions would increase significantly with improved early detection. It interferes too far in the natural process of reproduction, so the opponents of prenatal diagnostics.

Christiane Woopen, Chair of the German Ethics Council, also commented critically on the test: „Parents, in my opinion, have no right to have their child's genes examined unless there is a positive outcome for the child or the possibility of averting a health risk to the pregnant woman. "

As „Seal Online“ Hubert Hüppe (CDU), the Federal Government Commissioner for Disabled Persons, considers the test highly discriminatory and also illegal. Today, he will submit his report, which examined the legal aspect of the test and the ethical and social aspects of prenatal diagnosis, to the Federal Press Conference in Berlin. Also the ethics council of the Federal Government plans a statement until the end of 2012. (ag)

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Image: Dieter Schütz