New, safer down syndrome test brings ethical challenge

New, safer down syndrome test brings ethical challenge

Five medical institutions, including the National Center for Child Health and Development in Tokyo, plan to introduce a new type of prenatal diagnosis method to accurately determine if foetuses have Down syndrome, according to sources.

The institutions will introduce the method, which can detect the disease using samples of pregnant women's blood, in September at the earliest.

Compared with the conventional method in which amniotic fluid is collected by inserting a needle into a pregnant woman's abdomen, the latest method is much safer and easier to conduct.

However, if any chromosome abnormalities are found, they could prompt some mothers to have an abortion, making the method a likely source of controversy.

In addition to the NCCHD, the method will be introduced at Showa University in Tokyo, the Jikei University School of Medicine in Tokyo, the University of Tokyo, and Yokohama City University.

It will be used mainly for pregnant women aged 35 or older, as their babies have a higher probability of chromosome abnormalities.

The method will be implemented as part of clinical research to collect data on the Japanese population.

Testing will likely cost about 200,000 yen (S$3,188.25) and will not be covered by public health insurance schemes.

The method, which was established by US medical research company Sequenom Inc., was introduced in the United States last autumn.

The latest method checks for Down syndrome using a small quantity of a foetus' DNA contained in the mother's blood.

Humans normally have pairs of 23 chromosomes. If trisomy occurs on the 21st chromosome, in which the person has three copies instead of two, Down syndrome develops.

The latest method can detect the chromosome abnormality at a 99 per cent or higher rate of accuracy, and also can detect another two kinds of chromosome abnormalities that cause serious handicaps.

The method can be implemented around the 10th week of pregnancy, at least five weeks earlier than the traditional amniotic fluid check.

Currently in Japan, a method called maternal serum marker is used, but it can only determine the probability of Down syndrome and other disorders.

For absolute diagnosis, an amniotic fluid check is necessary. However, this traditional method raises a woman's risk of miscarriage to one out of 200.

In addition to an increase in the average age of women giving birth, the number of amniotic fluid checks has also been on the rise. In 2008, as many as 13,000 such checks were conducted.

Obstetricians and other practitioners in the institutions that will introduce the latest method will launch a volunteer group to study its potential problems, such as a rise in the number of abortions, on Friday.

The study group plans to establish guidelines for other medical institutions that wish to implement the latest method. It is considering such requirements as: there must be two or more doctors who specialise in genetic counseling, at least a 30-minute counseling session must be offered, and there must be pediatricians who can provide ongoing follow-up care.

Haruhiko Sago, chief of the perinatal centre of the NCCHD, said, "Though this latest technology can change the concept of prenatal diagnosis, if it is conducted too lightly, it may cause ethical problems.

"We'll implement the method carefully in conjunction with a proper counseling system."

Other methods for prenatal diagnosis include ultrasonography and villus check, which examines placental tissues.

Serious implications

The introduction of this latest method to check if a foetus has Down syndrome, which can be conducted safely using only blood samples and provides almost-certain results, will usher in a new era of prenatal diagnosis.

Knowing whether a baby will be born with a handicap or genetic disease could now become part of the standard health programme of pregnant women.

People naturally desire healthy babies. Unless doctors give sufficient explanations about the method in advance, it may be used without consideration for the potential implications, and lead to a dramatic increase in abortions.

The obstetricians and other experts who will voluntarily form the study group aim to establish guidelines to limit medical institutions that will be allowed to practice the method because they fear such repercussions.

However, the voluntary rules will have limited effects and thus a more effective framework is necessary.

First of all, the Maternal Health Protection Law does not permit abortions simply because a foetus has been diagnosed with an abnormality.

Currently, doctors conduct such abortions based on an extended interpretation of the law's clause that abortion is allowed "if a mother's health may be endangered."

Regardless whether prenatal diagnosis becomes easier, the results can still be severe.

Kunio Tamai, chief director of the Japan Down Syndrome Society, said, "I want doctors and others concerned to offer more explanations to pregnant women about how children with Down syndrome can grow up and have a [decent quality of life]."

How will we face such technological innovation that may affect the fate of numerous unborn lives?

The ethical task that lies ahead is great and there is no time to waste to begin the debate.

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