Critical trisomy tests widely used


Controversial trisomy tests used 10,000 times

In pregnant women, a blood test can be used to determine whether their unborn child has Down syndrome. These trisomy tests have been used approximately 10,000 times since they were introduced in 2012. But critics are still demanding that these tests be banned.

Test has been heavily criticized since its launch On March 21, World Down Syndrome Day, events are being organized worldwide to raise public awareness of the issue. On this occasion, discussions about a controversial diagnostic method will surely arise again. Because the trisomy blood test by the Constance company Lifecodexx has been heavily criticized since its introduction in 2012 with terms such as "selection", "discrimination against the disabled" and "illegal". As various newspapers report with reference to the dpa news agency, Lifecodexx Medical Director Wera Hofmann believes that the test has now become established. However, the Baden-Württemberg representative for the disabled, Gerd Weimer, opposes: "The designer baby is emerging on the horizon."

From the completed ninth week of pregnancy With the help of a blood sample from the pregnant woman, the so-called "PraenaTest" can rule out or confirm trisomies 21, 18 and 13 in the unborn child. The test has been used in several thousand pregnancies since its launch in August 2012. "We are keen on the 10,000," says Marketing Manager Elke Decker. About half of the blood samples came from Germany, but the test is also used worldwide. Samples from Switzerland, Hungary, Bulgaria, Turkey and Dubai were also sent. The test will be performed in women from the ninth week of pregnancy who have an increased risk of trisomies in the unborn child. Patients would usually have to pay the cost of 825 euros themselves. If a woman decides to take the test, the doctor's office sends blood samples to the company that contain snippets of the genetic makeup of the mother and child.

Date deliberately chosen for World Down Syndrome Day The laboratory then extracts the genetic material from which the child's DNA is determined from the blood sample in several steps, provided that its share is at least four percent. "We then see whether the amount of child-like genetic material for a particular chromosome is increased in order to determine a corresponding trisomy in the unborn child," says Hofmann. For example, in Down syndrome, the 21st chromosome is present in triplicate. This is characterized by physical abnormalities and reduced intelligence. The date was deliberately chosen for World Down Syndrome Day, which indicates this trisomy 21: March 21 symbolizes the triple presence of the 21st chromosome. In addition to the “PraenaTest”, two other non-invasive tests are currently available in Germany. Firstly, the “Panorama Test” from Natera and Amedes, which has been on the market since summer 2013, and the “Harmony Test” from the American company Ariosa, which has been available since autumn 2013. Both tests are evaluated in the United States.

Great accuracy of such blood tests confirmed As Heinz-Alfred Hagemann from the professional association of prenatal medicine specialists (BVNP) said, Lifecodexx was a pioneer in the non-invasive tests approved in Germany. The company is also “very strictly based on the Genetic Diagnostics Act” and has initiated a follow-up study in Germany. According to the company, the study will check in practice after delivery whether the result was correct. The accuracy is therefore 99 percent. The great accuracy of such blood tests was recently confirmed in a study published in the "New England Journal of Medicine". As a result, they are less likely to give incorrect results than conventional examination methods.

Disability officer calls for tests to be banned But there is still a lot of criticism of such tests. For example, some still see this as discrimination against people with disabilities. The test violated "the right to life as stipulated in the United Nations Convention on the Rights of Persons with Disabilities and must be banned nationwide," said the Baden-Württemberg commissioner for the disabled. "We need a broad social discussion about prenatal diagnostics as soon as possible." In the United States there are companies that could even test up to 80 parameters in the blood. "It starts with genetic defects to chronic diseases such as rheumatism or asthma," says Weimer. He was concerned that once this was used in Germany, the pressure would be too great for people who would give birth to a sick child without a previous test. "I think this is a terrible development." Shortly after the test was launched, Caritas Disabled Aid had asked politicians and society "to stand up for a society of diversity that also welcomes children with genetic disabilities in its midst." "Bonn Declaration" urged the organization, "every form of public social pressure on parents of disabled children must be countered."

Tests contain only a limited amount of information Lifecodexx rejects criticism of the tests. Hofmann says: "We see this as an excuse." In contrast to conventional invasive tests, such as puncturing the mother's cake, the non-invasive blood tests are risk-free. “Our company has decided to allow these tests. Criticizing the faster access now is flimsy. ”98 percent of the analyzes carried out so far are unremarkable. "If these women were all examined invasively, they would run the unnecessary risk of miscarriage." However, an inconspicuous test result does not automatically mean that the child is healthy. "About four percent of all newborns have an inherited illness," says Hofmann. "Other diseases arise, for example, from complications before, during and immediately after birth." Hagemann also said that the tests only contained a limited amount of information. "You can only say something about genetic dispositions," says the doctor. "But nothing about an evaluation of the whole child and his quality of life." (Ad)

Image: Gerd Altmann, Pixelio

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