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PRENATAL TESTING

Down syndrome blood test draws interest and ire

by Masami Ito

Staff Writer

Last summer, news that Japan was getting ready to introduce a new type of prenatal examination that requires only a simple blood test to detect whether a fetus has Down syndrome made headlines. News reports suggested hospitals were ready to start using the test in September.

But the controversial procedure immediately drew strong criticism that it could lead to “easy” abortions and discrimination against those with Down syndrome.

To prevent criticism of the new test from spinning out of control, the health minister at the time, Yoko Komiyama, said the Japan Society of Obstetrics and Gynecology should first establish ground rules. Now, more than six months later, the JSOG plans to adopt a set of guidelines later this month.

What sort of test is it?

This procedure is a blood test for women who are more than 10 weeks into their pregnancy to specifically detect the genetic chromosomal anomaly of only trisomy 13, 18 and 21. Trisomy 21 is the origin of Down syndrome, while trisomy 13 is called Patau syndrome and trisomy 18, Edwards syndrome, both resulting in serious heart defects, among other serious symptoms.

More than 20 medical institutions are expected to begin conducting clinical studies as soon as the JSOG announces its guidelines, including the National Center for Child Health and Development in Setagaya Ward and Showa University Hospital in Shinagawa Ward. The noninvasive test will not be covered by insurance and is expected to cost about ¥200,000. Outside of Japan, this test has been introduced in several other countries, including parts of the U.S. and Germany.

How accurate is it?

Sequenom Inc., the U.S.-based company that developed the test in 2011, boasts a highly accurate rate of detection — 99.1 percent — of trisomy 21. This number, however, is based on samples taken from women who were already known to be highly at risk of carrying a baby with Down syndrome. Medical experts say this positive predictive value will drop depending on the group sample. For example, it is said that 1 out of 250 women at the age of 35 will give birth to a baby with Down syndrome, and Haruhiko Sago, an expert on prenatal diagnosis at NCCHD, pointed out during a meeting discussing the blood test organized by JSOG that the accuracy of the test for this age group would drop to 79.9 percent, calling it “an extremely accurate yet nondefinite test.”

Are there other types of prenatal testing that have already been introduced to Japan?

Yes. First, there is sonogram screening, which is conducted during regular checkups for pregnant women. Sonograms allow doctors to see the fetus’ growth, as well as aiding in detecting some irregularities, including Nuchal Translucency, the swelling of the back of the neck in the early stages of pregnancy that can be a sign of Down syndrome or other chromosomal abnormalities. The triple or quad marker screen test is also a noninvasive blood test that will indicate the odds of the risk of giving birth to a baby with Down syndrome, trisomy 18 or an open neural tube defect.

This test examines the levels of certain proteins in the blood and calculates the odds. But neither the sonogram nor the marker test provide a diagnosis, with false positives also a major source of concern.

In 1999, the health ministry issued a statement that “doctors do not need to actively inform pregnant women” of the marker test because it can only estimate the odds. They raised concerns that it could be used as a mass-screening test to identify abnormalities in fetuses.

To get a definite answer, there are currently only two methods — a chorionic villus sampling or amniocentesis, both invasive procedures that involve injecting a long needle into the uterus. Although doctors performing this test take great care in ensuring there is no infection or harm to the fetus following the procedure, it is estimated that 1 in 300 pregnant women suffer miscarriages after undergoing amniocentesis. The percentage is even higher for chorionic villus sampling.

Do the chances of having a baby with Down syndrome increase with age?

Yes. In general 1 in 1,000 babies are born with Down syndrome.

Although the numbers may slightly vary, various research shows that the older the mother, the more likely she will carry a baby with trisomy 21. The possibility of a 25-year-old mother giving birth to a Down syndrome baby is said to be 1 in 1,041, but for a 40-year-old mother this figure skyrockets to 1 in 87.

What sort of guidelines are specialists trying to come up with for the new test?

In December, the JSOG issued a draft of the guidelines stating that the test should be limited to pregnant women who are 35 and older at the time of birth, those who have previously given birth to babies with chromosomal abnormalities, and women who have been diagnosed with the possibility of carrying such babies with earlier prenatal exams, including ultrasonography.

Medical institutions hoping to introduce the test should have full-time obstetricians and gynecologists with knowledge and experience in prenatal diagnosis, and it is preferable to have a certified genetic counselor.

Genetic counseling offers advice to would-be parents on prenatal diagnosis, including scientific explanation of the genes as well as the details of the abnormality, the treatment and what sort of aid is provided by the government.

However, there are just 149 gynecologists specializing in clinical genetics and 139 certified genetic counselors nationwide at the moment, not enough to provide patients with the support needed.

It is recommended that thorough genetic counseling be provided for expectant mothers before and after the test, and that institutions be able to conduct further invasive prenatal screenings if the patient desires them.

“The new prenatal genetic test using blood samples of mothers should only be held in facilities that can provide thorough genetic counseling . . . and it should be strictly refrained from being used as a mass-screening test for unspecified pregnant women,” the draft said. The JSOG sought public comments on the draft and the final set of the legally nonbinding guidelines are set to be approved this month.

What concerns have been raised over the controversial test?

One major concern is that the “extremely simple” test would lower the hurdle for pregnant women to get tested for prenatal diagnosis without any kind of knowledge of what the results may mean.

“Therefore, there is the possibility that pregnant women may make the wrong decision in a state of distress and confusion after the test results,” the JSOG draft warned.

Kunio Tamai, chairman of Japan Down Syndrome Society, explained to The Japan Times that his organization does not condemn the development of such medical technology itself, nor would it express opposition to the decisions made by pregnant individuals over whether to take the test. But Tamai expressed great concern that the test to specifically identify fetuses with Down syndrome and the two other abnormalities could lead to misunderstandings and discrimination.

“The test may end up actively recommending women to abort babies with Down syndrome and that could lead society to determine that those born with Down syndrome are destined to be unhappy and that their lives are worthless,” Tamai said.

How soon is the test going to be introduced?

Theoretically, clinical tests could begin once the JSOG officially issues the guidelines this month and once hospitals have the necessary staff and facilities to conduct them. The controversial test, however, has already been postponed since September and because each hospital is likely to hold internal discussions after the guidelines have been announced, it is hard to say when the tests will actually start being conducted.

One firm, however, has bypassed the current controversy. Tokyo-based Cell and Genetics Laboratory started a new business in February that sends pregnant women to medical institutions in the U.S. West Coast, Hawaii and Guam to check if their fetuses had any of the three chromosomal abnormalities.

The blood samples are then sent to Sequenom Inc. in California to be analyzed for a fee of roughly ¥350,000. JDSS’s Tamai condemned this practice, saying such tests should not be used for “commercial business,” expressing grave concerns that others could follow suit.

Current health minister Norihisa Tamura also expressed concern over the company going ahead with testing without waiting for JSOG guidelines.

“This is happening completely unrelated to the JSOG and I believe that it will have a major social impact,” Tamura told a recent news conference, adding that the ministry would look into the practice.

The Weekly FYI appears Tuesdays. Readers are encouraged to send ideas, questions and opinions to hodobu@japantimes.co.jp

  • weim

    There was 50 percent increase of down syndrome in Germany after Chernobyl. Downstream from Vermont Yankee power plant in the Deerfield river valley, incidence of Down syndrome increased tenfold. Japan is preparing to cleanse evidence of damage to the DNA of its own people done by fukushima.

  • ume

    I think this test is a good thing, but I’m not sure I really agree with it on principle.

    At the end of the day, having babies so late in life is a social problem. We should be encouraging women to have children at an age-appropriate time, which is (biologically) in their twenties or early thirties.

    Not only will tests like this cause more abortions, I think it will also encourage the mindset among women that its acceptable to have a child so late – its easy to test for abnormalities and easy to terminate. Such a decision should not be taken so lightly. There are many other dangers associated with a later-life pregnancy than downs syndrome – blood pressure, diabetes, raised rates of mother and infant mortality.

    • Chiara

      You realize that “older” mothers have always existed? Before contraception was widely available, women would go on having babies right up until the menopause – far past the early 30s, and with the same risk of Down’s as a modern woman having her first baby after that age.

      • ume

        Chiara of course! My own grandmother had her last child in her 40s, naturally conceived of course!

        However, the common trend of women consciously leaving having their first child so late is a modern phenomenon, caused mainly by women putting their education and career first. These women in the past would theoretically be able to conceive right up to the menopause, however the natural fertility decline and decrease in egg quality will make conceiving (and carrying to full term) a child after 40 difficult for many women. The miscarriage rate is very high for over 40s.

        Now more and more women are unable to conceive naturally at the time they wish to get pregnant (ie – late thirties or early forties) and are undergoing IVF and other procedures to get pregnant, where as these procedures were simply not available in the past. The number of “older” mothers is much higher now as a result.

        Also, while the risk of chromosonal abnormalities was the same for over 40s in the past, many of the women would NOT be having their first child in their 40s. They might already have 2, 3, 4, 5 + children, and therefore the biological clock would not be ticking quite so loudly as for women in their 40s today, who are trying to have their first baby so late, and often failing.

        It must be absolutely heartbreaking for these women and they have my upmost sympathy. On a personal note, I am very glad I made the decision to have my children young.