Minggu, 01 Mei 2011
The danger of unreliable paternity tests (BAHAYA TES UNTUK MENENTUKAN AYAH DARI JANIN YANG TIDAK DAPAT DIANDALKAN)
KATHRYN* was on the brink of booking an appointment at the abortion clinic. In October 2008, she received an email she'd been dreading: the results of a prenatal paternity test suggesting she was pregnant by a man other than her boyfriend.
She was delighted at the prospect of having her boyfriend's baby, but couldn't bear to have the other man's child. "I said to my counsellor that there's absolutely no way I can go through with this pregnancy if it's that guy's," Kathryn recalls.
Fortunately, she decided to have a second test. Conducted by one of the UK's leading forensic genetics labs, this showed conclusively that the other man could not be the father. Today, Kathryn dotes on her daughter and looks back on the incident with horror.
Kathryn is not the only person to have received flawed results from the Canadian laboratory that ran the initial test she purchased. In an investigation covering similar cases, plus samples we submitted ourselves, New Scientist has discovered errors made by the lab, including DNA profiles for fetuses and possible fathers that are inconsistent with the known ancestry of the human genome. It even generated a DNA profile for a "fetus" when the woman tested was not actually pregnant.
The test is run on a sample of the woman's blood and cheek swabs from possible fathers. Our investigation suggests that the results are unreliable - with potentially devastating consequences. "Paternity testing can have profound effects on people's lives and, when there is an unborn child involved, may lead to a termination," says Denise Syndercombe Court of Barts and The London School of Medicine and Dentistry, who ran the follow-up test for Kathryn.
Selling genetic tests direct to the public is a burgeoning industry, with people turning to their DNA to explore their health and probe their ancestry as well as to resolve contested paternity.
Our findings highlight the potential dangers of allowing companies to operate without regulation and quality control. Paternity testing labs are free to operate without accreditation unless they offer results for use in court. "This has been able to fly under the radar," observes Gail Javitt, a lawyer with the Washington DC firm Sidley Austin, who has studied the regulation of genetic testing.
Kathryn and other pregnant women who ordered the blood test were keen to avoid a procedure called an amniocentesis. This is normally used to detect fetal abnormalities such as Down's syndrome, and involves inserting a needle into a pregnant woman's belly to take a sample of amniotic fluid containing cells from her fetus. The procedure carries a small risk of miscarriage, so genetic testing labs have been working on methods of isolating fetal DNA from a pregnant woman's blood.
Geneticists have had some success in developing tests on maternal blood to detect fetal genes that are not also carried by the mother. For instance, it's possible to determine fetal sex by detecting sequences from the male Y chromosome. But these methods have not easily translated to paternity testing.
Despite this, several websites offer prenatal paternity tests based on a woman's blood. Quoted prices start at about $960 and while the technical descriptions differ a little from site to site, for those New Scientist found, the tests are run by a lab in Toronto, Canada, operated by a company called the Health Genetic Center. The lab's director is Yuri Melekhovets, who trained as a geneticist in Moscow, Russia.
The lab began to develop a blood test for paternity in 2000. By 2002, some customers who sought a second opinion from labs running standard paternity tests had received contradictory results, suggesting that the blood test was prone to error. And the following year, an Arizona court ordered that one of Melekhovets's companies, and a firm called Genetest, which had sold his prenatal blood test, should pay substantial damages to one couple who were given an incorrect result (see "Four lives changed forever"). The action brought against these firms was not defended and a representative of the Toronto lab said that Melekhovets had never been made aware of the ruling.
One company, the Paternity Testing Corporation (PTC) of Columbia, Missouri, has run tests for several customers of the Toronto lab, and found that its conclusions about paternity were inaccurate. "We have identified a series of errors over the course of the past eight years," says Joe Gorman, PTC's general counsel. After learning of these cases, and other errors identified by Syndercombe Court's lab at Barts, New Scientist decided to investigate further, focusing on recent tests.
The Toronto lab's testing procedures have evolved over time. Initially, it claimed to concentrate small numbers of fetal cells from the woman's blood. Today, the lab's prenatal testing website stresses the use of "cell-free" fetal DNA, which passes across the placenta from fetal cells that have broken down.
ADMIN NOTE :
Pada intinya, uji tes untuk menentukan ayas dari seorang bayi sebelum kelahirannya sangat berbahaya, ini dapat memicu seorang wanita mengaborsi bayi yang dikandungnya dikarenakan ia tidak mau melahirkan seorang anak dari selain orang yang dicintainya,,,, ( SEMOGA DI INDONESIA GAK ADA YA, KALAU ADA ITU BERARTI MEMALUKAN),,, HOHOH
tes ini biasanya dilakukan di negara yang tingkat free sexnya tinggi.. INDONESIA GIMANA NICH?... ya semoga GAK ADA.....
TAPI ANEH BUAT KITA, BERANI BERBUAT, HARUSNYA BERANI BERTANGGUNG JAWAB... MAU ENAKNYA, HARUS MAU MENERIMA RESIKONYA.....SEMOGA yang membaca ini tidak termasuk ya.... heheheh