DNA Test Down Syndrome Improved

DNA testGood news for couples who are expecting a baby, as the latest DNA test to screen Down’s syndrome has improved. A new study has shown that the test has 10 times better results compared to previous methods and the test can already be taken in the early stage of a pregnancy.

Dr. Diana Bianchi is the lead study author and executive director of the Mother Infant Research Institute at Tufts Medical Center in Boston. For the study, Bianchi compared the effectiveness of both previous methods and the new test, called Verifi. The results were astounding. A group of 1,914 pregnant women was recruited by researchers and participated in a standard test and the new test to screen for Down’s Syndrome as well as other diseases in the unborn child. Researchers found that the new test was more accurate, with only 0.3 percent of false positives, while the standard test showed a 3.6 percent of false positives. Bianchi says, “The new DNA test showed a significant improvement in screening for Down’s Syndrome and it will give women the opportunity to have a safe and more accurate test in the early stage of pregnancy. The test can already be done in the 10th week.”

The new test sequences the mother’s DNA from the placenta and maps it to different chromosomes. If the results are positive, the mother is still required to undergo a diagnostic test to find out more details about the child’s disorder. Dr. Michael Greene, chief of Obstetrics at the Massachusetts General Hospital, says, “Previous tests for screening Down’s Syndrome scares and intimidates a large amount of women, especially those who undergo diagnostic testing only to find out that their unborn child is healthy. With the new test, the number of women who were falsely labeled as having an abnormal baby is much smaller. It is a major advantage.”

With over 6.6 million pregnancies and 4 million births in the U.S. each year, the test is not only a major improvement for expecting parents. It can also create business opportunities for biotechnology companies, as some are already selling the new DNA tests, priced between $700 and $2,500. Some doctors say the DNA test is especially useful for pregnant women who are older than 35 years old, as the risk factors are known to be higher among these women compared to younger women. In addition, the test could reduce the number of more invasive screening, such as biopsies, which come with a small risk of a miscarriage during testing. Although numerous biotechnology companies have started selling the test, some doctors remain skeptical and prefer to observe the results and the effectiveness before using it on their patients. Dr. Susan Klugman, director of Reproductive Genetics of Montefiore Medical Center, says, “The costs of the test are also a major factor in the fact that some doctors are skeptical at the moment.”

In the U.S., one in every 691 babies is born with Down’s Syndrome. Although the risks increase with the mother’s age, 80 percent of babies with Down’s Syndrome are born to mothers under the age of 35 years old. According to the National Down’s Syndrome Society, this is due to the higher fertility rate in younger women. In recent decades, the life expectancy of people with Down’s Syndrome has dramatically increased, from 25 years old in 1983 to 60 years old now.

The new DNA test, which improved the screening for Down’s Syndrome, also raises some controversy, as pregnant women are now able to decide whether or not to keep the baby, when the test shows positive results for Down’s Syndrome.

By Diana Herst

Scienceworld Report
Headlines & Global News

3 Responses to "DNA Test Down Syndrome Improved"

  1. Metin Gunduz (@metingun2)   March 1, 2014 at 3:39 pm

    Certain `helpful` details about the test `Verify` should be clarified since it is not mentioned at the article above .
    It is basically a blood test drown from the arm of pregnant women . Test Looks for `Cell-free fetal(baby) DNA (cffDNA) of baby`s DNA circulating freely in the mother`s blood stream. During the test roughly % 7 to % 20 Cell free Baby`s DNA fragments extracted from the mother`s blood and the DNA fragment identification technique is called `massive parallel sequencing` , 1 million to 43 billion short reads (50-400 bases each DNA fragment ) per instrument run can be tested .
    Mother`s blood is generally drawn ` after 10 weeks of pregnancy but can be tested as early as 5 weeks of pregnancy , and the test basically calculates the number of copies of each chromosome pairs from the cell free baby`s DNA fragments present in the mother`s blood , in other words if there are too many or too few copies of certain chromosomes present in the baby .
    So the test counts the `Total number of pairs of 22 Autosomal ( Numbered according to their sizes from 1 to 22 ) and X and Y sex chromosome copies `
    Each Autosomal Chromosome normally has 2 pairs , Trisomy means 3 Chromosomes(Extra one more Chromosome`total 3` instead of normal 2 Chromosomes ) Trisomy of 21 is Down Syndrome which has 3 copies of Number 21 Chromosome .
    Verify Test results are listed as 3 possibilities 1- No Aneuploidy (Chromosomal number abnormality) Detected , 2- Aneuploidy Detected 3- Aneuploidy Suspected .
    Babies sex boy or girl also can be detected if requested as an option at the test .


  2. Rella   March 1, 2014 at 3:10 pm

    It is Down syndrome, not Down’s Syndrome.

    • Lauren   April 3, 2014 at 4:46 am

      Actually it was originally labelled Down’s Syndrome after John Langdon Down as he originally identified it. However, in some countries, such as the US they have now dropped the ‘s, but we still call it Down’s Syndrome in the UK.

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