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Test tube baby born using a new method of artificial insemination
The first baby after artificial insemination, whose genome was known in advance, was born in England in June. The embryo would have been sorted out if it had been sick.
This morning in the UK it was confirmed what experts had been predicting for months: the entire genome of artificial embryos can be completely deciphered before they are transferred to the mother. British reproductive geneticist Dagan Welss from Oxford University announced earlier this morning at the European Reproductive Medicine (ESHRE) meeting in London that the first baby to undergo this procedure as an embryo was born in the United States in June. The genes could be read even before the mother was pregnant. The parents of the baby named Connor had tried unsuccessfully for years to have children. After all, the 36-year-old mother's pregnancy was successful after artificial insemination and the selection of the genetically healthy embryo.
Lower in price
The first tests with the so-called "Next Generation Sequencing" (NGS) had been successfully used by a team led by Wells from the Biomedical Research Center at Oxford University. "NGS provides unprecedented insights into the biology of embryos," says Wells. Previously used methods would only have a maximum success rate of 30 percent. Although the reason for this is not known, it is suspected that this could also be due to hidden chromosome defects The new method, which is also said to be cheaper than previous methods, is now to be tested in a larger study.
Decipher and analyze the entire genome
The new process has also been used by other couples. According to the British researchers, the birth of another baby is imminent, in which the genome was deciphered using the same method before being transplanted into the womb. The new test procedure is a further development of pre-implantation diagnostics (PID). This is used to specifically examine embryos for specific inherited diseases before they are used for artificial insemination. To do this, individual cells are removed from the embryo and genes in the genetic material of the cells are individually tested for defects. It is usually about defects that lie on only one gene, the monogenic hereditary diseases. If a parent is suspected of being predisposed to such an inherited disease, embryos can then be tested. Thanks to the further development, the scientists can now decipher and analyze the entire genome of the tiny amount of genetic material from two or three cells of the embryo.
"Baby Take Home Rate"
At the moment, the scientists around Wells are not concerned with the complete genome decoding, but the aim is to achieve a particularly high pregnancy rate with IVF treatment, so that the patients are spared repeated treatment cycles and hormone doses. IVF (in vitro fertilization - Latin for "fertilization in the glass") is an artificial fertilization that has been used since 1978 to treat the unfulfilled desire to have children. Since then, three million children have been born worldwide using test tube fertilization. In Germany, some of the costs are covered by the health insurance companies. The rate of successful births after artificial insemination is referred to as a "baby take home rate" by reproductive doctors.
Pregnancy rates of at least 70 percent
With the new method, the scientists read the genetic molecules only superficially in order to determine a possible chromosome disorder (aneuploidy) of the embryo. This would be the case if the cells did not have the correct number of 46 chromosomes. Missing (monodomies) or excess (trisomies) chromosomes are considered to be the skin cause for the failure of pregnancy treatment. Such deviations pose a very high risk that the embryo cannot develop or lead to a miscarriage. For example, in trisomy 21, the cause of Down's syndrome, around two thirds of the affected fetuses die in the womb. Based on previous experience with the chromosome tests, IVF doctors achieve pregnancy rates of at least 70 percent in the first attempt. Regardless of the age of women, the success rate remains stable.
German legal situation unclear
It is controversial among lawyers whether the new method would be permitted in Germany under the PID law. Parliament had only recently allowed PGD to be introduced after years of political and ethical controversy, but within narrow limits and on the assumption that little more than 200 such studies would be carried out annually. However, if the new method were to be used as a routine check-up for fertility treatments, tens of thousands of tests on embryos would result every year. The majority would not pass and would be sorted out in the laboratory before nature did. Klaus Diedrich, chairman of the PID commission at the German Society for Gynecology and Obstetrics, believes it is unlikely that the method will be introduced in Germany: "In Great Britain, screening was only carried out on suspicion; this is unthinkable in Germany." (Ad )
Image: Dieter Hopf / pixelio.de