PHLB09H3 Chapter Notes - Chapter 9: Tay–Sachs Disease, Prenatal Diagnosis, Dominance (Genetics)
Chapter 9: Genetic Choices
Vaughn
Genetic Testing
- Human Genome Project—tracing of the human genome—- it is not possible to check
for genetic disorders by looking for changes in a person’s DNA
-Genetic Testing— ability to check for genetic disorders by looking for changes in a
person’s DNA
- Now over 2000 tests designed to detect disease
Testing Done For Several Reasons:
1. Newborn Screening
-to uncover disease for early treatment
- First mandatory genetic testing was for phenylktonuria (PKU)—a disorder resulting in
profound mental retardation when not treated early with a special diet
2. Carrier Testing
- to determine whether someone is a carrier of a type of genetic disease as an
autosomal recessive disorder
-i.e. cystic fibrosis, sickle cell, Tay-Sachs
3. Predictive Testing
- to see of someone will get a disease later in life
- often recommended for people who have a family history of a genetic disorder
4. Diagnostic Testing
- to confirm or rule out a genetic disorder in someone with symptoms
5. Prenatal Testing
- To determine if a fetus has genetic abnormalities likely to cause physical impairments
—ie if the mother is above 35, there is evidence of hereditary disorders in the family,
ancestry/ethnicity suggests there is a chance of developing a certain disorder
-Most common prenatal test is amniocentesis—which analyzes the amniotic fluid and
chronic villus sampling (CVS)—which tests a few cells from the placenta
6. Preimplantation Genetic Diagnosis (PGD)
- to test embryos produced through IVF for genetic abnormalities
- Typical procedure is to remove 5-8 cell embryo for testing and screening for genetic
defects
- Costly and preserved for cases when there is a high chance of giving birth to a baby
with Down Syndrome or Tay Sachs disease
Document Summary
Human genome project tracing of the human genome - it is not possible to check for genetic disorders by looking for changes in a person"s dna. Genetic testing ability to check for genetic disorders by looking for changes in a person"s dna. Now over 2000 tests designed to detect disease. Testing done for several reasons: newborn screening to uncover disease for early treatment. To determine if a fetus has genetic abnormalities likely to cause physical impairments. Ie if the mother is above 35, there is evidence of hereditary disorders in the family, ancestry/ethnicity suggests there is a chance of developing a certain disorder. Most common prenatal test is amniocentesis which analyzes the amniotic fluid and chronic villus sampling (cvs) which tests a few cells from the placenta: preimplantation genetic diagnosis (pgd) to test embryos produced through ivf for genetic abnormalities. Typical procedure is to remove 5-8 cell embryo for testing and screening for genetic defects.
