Genetic Screening

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Genetic Screening

• Prepared By Andrew Davidson and Phil Romanin
• Prepared For Mr. Miller
• SCN 1D0-05
• Westlane Secondary School
• Due Date Thursday, May 25th , 2000

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What is Genetic Screening?

• Genetic Screening is when fluid surrounding the
  fetus is extracted or cells are taken from the
  chorion. From the extracted fluid or cells, the
  chromosomes are examined, and by comparing the
  chromosomes, genetic disorders can be discovered
  and the sex can also be determined.

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What can Genetic Screening Detect?

• Genetic Screening can detect the following
• Down's syndrome
• Tay-Sachs disease
• Open Neural Tube Defects
• Abdomen defects
• Some Chromosome Abnormalities

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First method of Genetic ScreeningAmniocentesis

• Amniocentesis is relatively
• safe and is the most common
• genetic screening method used.
• It involves taking amniotic
• fluid from around the fetus. By
• treating the fluid, the
• chromosomes are made visible
• for examination. The
• examination can reveal genetic
• disorders and the sex.

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Second method of Genetic ScreeningChorionic
Villus Sampling (CVS)

• CVS is the newer of the two
• methods. CVS involves
• obtaining cells from the
• chorion surrounding the
• Embryo. The cells can be
• Analyzed and early results can
• be in by 2-3 days and final
• results by 10 day, much faster
• then amniocentesis which take
• 2-3 weeks for results.

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The Negatives of Each Method
Amniocentesis CVS

• The test is done late in the pregnancy and the
  results become available between the 14th 18th
  week, leaving the mother with few options.
  Abortion is considered only safe before three
  months.
• The waiting period for the results (2-3 weeks) is
  considered to long for the mother to bear.

• The chorion cells are taken because they are
  similar to the ones found in the fetus. The
  problem is that some abnormalities occur in the
  chorion cells that dont occur in the fetus. This
  may lead the mother to abort.
• In order to gather the cells, penetration of the
  cervix is needed, this poses the risk of
  infection

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Percentage of Miscarriages
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Why is Genetic Screening Controversial?

• Some people do not like genetic screening
  because the believe that it be could be used for
  bad not good. For example if they found that the
  fetus had a disorder that could not be cured, the
  mother may choose to abort the birth. Also if
  genetic screening finds that the fetus is going
  to get diabetes when it gets older, an insurance
  company may not choose to insure that person.

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Bibliography

• Tests Done During Pregnancy. Chorionic villus
  sampling. http//www.bu.edu/cohis/teenpreg/test
  ing/cvs.htm. 2000
• Tests Done During Pregnancy. Amniocentesis.
  http//www.bu.edu/cohis/teenpreg/testing/amnio.ht
  m. 2000
• Bornstein, Sandy Amniocentesis. Microsoft
  Corporation (Encarta). 1999 ed.
• Chorionic Villus Sampling (CVS). Chorionic
  Villus Sampling (CVS). http//www.stanford.edu/
  holbrook/CVS.html. 2000