Genetic Testing Ethics Flashcards
what is genetic testing?
a laboratory test of a person’s genes or chromosomes for abnormalities, defects or deficiencies, including carrier status, that are linked to physical or mental disorders or impairments, or that indicate susceptibility to illness, disease or other disorder, whether physical or mental, which test is direct test and not an indirect manifestation of genetic disorders
what are the two types of genetic testing?
- diagnostic: determines cause of a disease
2. predictive: determines risk for a disorder
for which diseases is predictive genetic testing done?
- cystic fibrosis
- breast cancer
- huntington’s
what are BRCA1 and BRCA2?
TSGs!!
so if these genes are mutated, it’s linked to hereditary breast and ovarian cancer
what are some reasons to do genetic testing?
- woman delivers a stillborn child with physical signs of a genetic illness
- pregnancy over 34
- if standard prenatal screening test had an abnormal result
- confirmation that a medical problem has a genetic cause due to a particular syndrome
- if there’s a family incidence of an inherited illness
- there’s already a child with a severe birth defect
- woman has had two or more miscarriages
what are the pros to genetic testing?
- advance medicine and public health
- correlate disease to genes
- allow individuals and families to make lifestyle, fertility and planning decisions.
- may be reassured by a negative result
what are the cons to genetic test?
- payment
2. potential to lose health insurance
what’s the nondiscrimination information act?
prohibits group health insurance plans and issuers of coverage from basing eligibility or adjusting premiums on the basis of genetic information
insurance companies cannot require or purchase results of genetic tests
prohibits employers from firing, refusing to hire or otherwise discriminating against (potential) employees
what are the implications of genetic testing?
- choices to terminate pregnancy
- choices not to have children
- presymptomatic treatment of patients identified with CF has not been shown to delay onset of disease.
- genetically affected children may be discriminated against, by being ‘classified’ by education systems
what is 23andMe?
biotech firm tests a saliva sample for $100
provides information about:
- who your ancestors were
- the risks you have of developing various diseases
what is PGD?
pre-implantation genetic diagnosis
what are the current prenatal genetic testing options?
- amniocentesis
- chorionic villus sampling
- multiple-marker screening test
- cell-free fetal DNA test
what is amniocentesis?
needle aspirates amniotic fluid through abdomen/uterus at 16 to 18 weeks
detects:
- chromosomal abnormalities
- genetic disorders
- neural tube defects
what is CVS?
needle aspiration of chorionic villi through abdomen/uterus or cervix at 11 to 13 weeks
detects:
- chromosomal abnormalities
- genetic disorders
what is multiple-marker screening test?
maternal blood draw at 15 to 20 weeks
detects:
- down syndrome
- edwards syndrome
- neural tube defects
what is cfDNA?
maternal blood draw at 10 weeks
detects:
- DS
- patau syndrome
- edwards syndrome
- sex chromosome disorders
does insurance cover genetic testing?
most times no
they’re not mandated to
what does HESC stand for?
human embryonic stem cell research
what is gremlin gene therapy?
eliminate “bad” genes from the individual and from his descendants
has been attempted on human embryos in China using CRISPR with limited success
what is somatic gene cell therapy?
normally functioning gene is inserted into the patient’s genome using a viral vector
inserted gene is translated into a normal gene product (a protein)
new genes are not inserted into the patient’s germ cells, so no changes are passed on to offspring
what is CAR-T treatment?
Chimeric Antigen Receptor T-cell (CAR-T) Treatment
“Program” T-cells to target cancer cells
how do you treat mitochondrial disorders?
use a donor egg with healthy mitochondrial DNA and remove the DNA from the nucleus
maternal DNA is places in the nucleus of the donor egg
paternal sperm fertilizes this donor egg
so the resulting embryo has DNA from 3 individuals
when are HESC harvested?
derived in vitro at day 5 of embryonic development
HESCs are harvested from inner cell mass of blastocyst which would eventually become embryo
embryonic stem cell lines may continue to divide for many months to years
the embryo itself though is destroyed
what’s the 14 day rule?
prohibits experimentation on human embryos older than 14 days
this is the point at which body axes and the neural tube begin to form
it’s before the development of a nervous system that could allow the embryo to feel pain or think (primitive streak)
what are some possible alternatives to HESCs?
Umbilical cord blood
Stem cells found in amniotic fluid
Induced Pluripotent Stem Cells (iPSCs)
Synthetic Human Embryo-Like Entities (SHELEs)
what is umbilical cord blood used for?
currently used as an alternative to bone marrow transplantation
what are iPSCs?
Induced Pluripotent Stem Cells
convert adult human skin cells into cells with the properties of HESCs
activate 4 genes in the adult cells, utilizing a retrovirus, to reprogram into pluripotent cells
unknown if they have the same potential as HESCs and they may induce tumors due to the use of retroviruses
what are SHELEs?
Synthetic Human Embryo-Like Entities
formation of vascularized embryoid bodies through vascularization and tissue engineering
current ethical and legal guidelines don’t recognize SHELEs and limit the use of methods that might allow research in tissue engineering to proceed
what is SCNT?
Somatic Cell Nuclear Transfer
nucleus of an egg is removed and replaced by the nucleus of a mature somatic cell
what is the cloning process?
skin cells from adult get added to an egg and then an electric pulse causes skin cels to fuse with the egg
then the cell divides and the early stage embryo is implanted in surrogate mother
what are the applications for SCNT?
- reproductive cloning = create cloned individuals
- therapeutic cloning = create cloned stem cells - grow an organism genetically identical to the patient—no risk of organ rejection
what’s the genetic view of when a human begins to exist?
you become a human being with the emergence of the one-cell zygote at fertilization (acquisition of a novel genome)
whats the embryologic view of when a human begins to exist?
you become a human being at gastrulation (acquisition of an individual physical identity)
each cell is alive, but they only become parts of a human organism around day 16
so disaggregating the cells at day 5 to derive HESCs does not destroy a human being
what is the neurological view of when a human begins to exist?
when the human EEG pattern is acquired
after week 24 of gestation
what is the viability view of when a human being begins to exist?
a fetus should be considered human when it can survive on its own
25 weeks
what happens to left over embryos after infertility treatment?
most HESCs are derived from “left-over” embryos after infertility treatment!
the problem is that these HESCs are not diverse enough to address immune rejection by recipients of stem cell transplants
researchers need to study particular genetic mutations; this requires cloning technology
