This article about new tests for Down syndrome said that one company reported the results of its test on 858 women at a meeting of the Society for Maternal-Fetal Medicine in San Diego last month. While the company did report information about the methods used by its new test at the society's meeting, the data on the test's accuracy were presented only at a briefing for analysts and investors that was held concurrently with the meeting.
New Safety, New Concerns In Tests for Down Syndrome
Tuesday, February 24, 2009
A handful of biotech companies are racing to market a new generation of tests for Down syndrome, a development that promises a safer way to spot the most common genetic cause of mental retardation early in pregnancy even as it weaves a thicket of moral, medical, political and regulatory concerns.
Doctors recommend that all pregnant women be offered screening for Down syndrome, and about half of women undergo the tests. But the current tests often produce confusing, ambiguous results, unnecessarily alarming couples or falsely reassuring them. The new tests are designed to offer more definitive results early in the pregnancy.
But with the first new approach due to become available this spring, the tests are renewing questions about why regulators do not require such innovations to be proved reliable before being offered to the public.
Abortion opponents, meanwhile, fear that the technology may prompt more couples to terminate pregnancies. And advocates for the disabled, noting that couples are often poorly informed about the syndrome, worry that more of them may feel pressured to abort. They also fear a dwindling number of those born with the condition, along with the prospect of increased discrimination against them and their families.
"We have a history in this country of a eugenics movement where people tried to eliminate certain people from the gene pool," said Andrew J. Imparato of the American Association of People With Disabilities. "People could start wondering, 'How did you get born?' "
The quandaries being raised by the tests illustrate the morass of issues that will arise as scientific and technological advances produce more tests to identify markers for genetic conditions -- before conception, during pregnancy and even after birth.
"This is just the first wave of a salvo of new tests," said W. Gregory Feero of the National Human Genome Research Institute. "We are at a time where you will be able to test for many things and will be left with many serious questions -- both scientific and moral -- about how to interpret and what to do with the information."
The new tests for Down syndrome come as advocates pressure Congress to fund a law passed last year aimed at ensuring that couples get accurate information about genetic conditions and at providing support for women who decide to keep their affected children or put them up for adoption.
"These tests make this all the more important," said Madeleine Will of the National Down Syndrome Society, which is seeking $25 million over five years to implement the legislation. Society members are gathering in Washington this week to lobby on this and related issues.
In 2007, the American College of Obstetricians and Gynecologists recommended that all women be offered screening tests for Down syndrome, which causes mental retardation and other health problems. The current tests consist of a combination of blood tests and ultrasounds. Depending on the results, the women may then undergo either amniocentesis or chorionic villus sampling (CVS) to confirm or rule out the diagnosis.
But the screening tests often produce imprecise results, and amniocentesis, the most common definitive test, can cause miscarriages and is not usually performed until the second trimester, when the termination of a pregnancy is much more traumatic and difficult to obtain.
The new tests take advantage of techniques that can isolate and analyze tiny bits of genetic information from the fetus that circulate in a woman's bloodstream, in this case from cells or free-floating snippets of DNA or the related molecule RNA.