Wednesday, February 6, 2013

Noninvasive Test for Chromosomal Defects in the Fetus

Tuesday, February 5, Cody L. and I presented Noninvasive Test for Chromosomal Defects in the Fetus. This test is new technology in development to detect chromosomal abnormalities in a fetus through a mother’s blood sample. Using Massive parallel sequencing, the fetal DNA can be isolated in the blood and read in many short bursts at one time. This allows for the DNA to be decoded and assembled together to reflect the entire genome.
The positive side to this technology is the safer method of testing. Currently, more dangerous or less accurate tests are used. An amniocentesis is the most reliable method of currently determining chromosomal defects in the fetus, yet it is coupled with the highest risk. In order to gain a sample of the amino, a needle is inserted through the mother’s belly into the sterile amniotic fluid. This needle can introduce pathogens causing and infection, a or even lead to a spontaneous abortion upon entry, which is argued to be between a 1 in 200 or 1 in 1600 risk. There are also methods of calculating a probability of defects with in the fetus either by a visual clues or maternal hormone screening. Neither of these methods are very reliable, however, and generally lead to an amniocentesis for confirmation. The new technology and methods being developed allows for a harmless blood draw from the mother. The blood can be analyzed for fetal DNA fragments present. These fragments can then be isolated and decoded. The process of decoding is preliminarily test to be just as accurate as MicroArray technology, currently the most accurate method of decoding and translating DNA. 
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4 comments:

  1. R.BurkeFebruary 7, 2013 at 11:34 PM

    This presentation sparked a lot of conversation in our class and I felt that there were two main topics of discussion, one technological and one ethical. The technological discussion revolved around future advances in "designer babies" and the ideas of safety for both mother and fetus with this test and an amnio. Ethically, there were several issues that I felt could never be solved as they were of a personal nature but some points were made about the ties between a mother and a child, which reminded me of "Born for Love" by Bruce D. Perry and Maia Szalavitz. This book discusses the ties made between mother and child, biologically from birth on and what happens when children don't make these ties.

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  2. CodyLFebruary 8, 2013 at 1:05 AM

    The negative side of this new technology is that there is a risk of false positives and false negatives. Also it only screens for a small percentage of possible defects. For example, it cannot screen for monosomies, a situation where there is only one chromosome instead of the usual pair. While it is much safer than previous methods, it is not 100% correct. Since the initial study only used a sample size of 40 fetuses, there is a large margin of possible error present in the information advertised. It needs to be tested in a major clinical study before it goes down the road to being approved by the FDA. This can cost millions of dollars and will drive up the cost of the tests when it is first introduced into medical practice. Another major fear if this technology were to become common place is the possibility of designer babies and genetic bias. Insurance companies could choose to require this for expecting mothers to see if the child may have any preexisting conditions. Then it is up to the insurance company to decide whether they will provide coverage for the child. Gattaca is a movie that delves into the possibility of a future where your future is decided by your genetics. Ethics plays a large part in this as well because a young mother, whose child may be born sick, must decide whether or not to abort her child. The new advances in testing for chromosomal defects in fetuses have potential to allow for even more advances in the medical world, but as of right now it is necessary to ask ourselves if we are ready to take on the responsibility and cost that comes with it.

    Turkle goes into depth about genetics and technology.

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  3. UnknownFebruary 8, 2013 at 10:39 AM

    Is any scientific test really 100%? I know anyone who has had a lab at LSU has to know how to calculate error and uncertainty in the first week. Imperfection is part of progress and innovation. I feel like this is a step in the right direction for safe and practical medicine, This does not even crack the top ten list of problems in modern medicine.

    Carr says in The Shallows that "We are too prone to make technological instruments the scapegoats for the sins of those who wield them. The products of modern science are not in themselves good or bad; it is the way they are used that determines their value." The way this is being used for precautions and safety of a mother and child (more reliably than in the past) determines its value.

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  4. UnknownFebruary 19, 2013 at 12:25 PM

    Although I don't think I would use this technology personally, being a Biochemistry major I find this technology extremely interesting. Although I don't find this technology to be against my ethics or religion, the actions that may come after this technology may be against my ethics. I think if we keep building on this technology we may have to ask ourselves "How far is too far?". I believe this is a big theme within all of technology. Some clinics already allow families to pick out the gender of their child. It scares me that within a few decades families may be going to fertility clinics to pick out their babies like they pick out cars.

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