1. Cape Biology

2. What is Gene Therapy
According to the… Gene therapy is an
experimental technique that uses genes to
treat or prevent disease. In the future, this
technique may allow doctors to treat a
disorder by inserting a gene into a patient’s
cells instead of using drugs or surgery.
Researchers are testing several approaches
to gene therapy, including:
 Replacing a mutated gene that causes
disease with a healthy copy of the gene.
 Inactivating, or “knocking out,” a mutated
gene that is functioning improperly.
 Introducing a new gene into the body to help

3. Cont….. What is gene therapy
Imagine that you accidentally broke one of your neighbor's
windows. What would you do? You could:
 Stay silent: no one will ever find out that you are guilty,
but the window doesn't get fixed.
 Try to repair the cracked window with some tape: not the
best long-term solution.
 Put in a new window: not only do you solve the problem,
but also you do the honorable thing.
 What does this have to do with gene therapy?
You can think of a medical condition or illness as a
"broken window." Many medical conditions result from
flaws, or mutations, in one or more of a person's genes.
Mutations cause the protein encoded by that gene to
malfunction. When a protein malfunctions, cells that rely
on that protein's function can't behave normally, causing
problems for whole tissues or organs. Medical conditions

4. How Does Gene Therapy Work?
 Gene therapy is designed to introduce genetic
material into cells to compensate for abnormal genes
or to make a beneficial protein. If a mutated gene
causes a necessary protein to be faulty or missing,
gene therapy may be able to introduce a normal copy
of the gene to restore the function of the protein.
 A gene that is inserted directly into a cell usually does
not function. Instead, a carrier called a vector is
genetically engineered to deliver the gene. Certain
viruses are often used as vectors because they can
deliver the new gene by infecting the cell. The viruses
are modified so they can’t cause disease when used
in people. Some types of virus, such as retroviruses,
integrate their genetic material (including the new
gene) into a chromosome in the human cell. Other
viruses, such as adenoviruses, introduce their DNA

5. Examples Of Gene Theropy
 An example of gene therapy is?
 A) Injection of insuline into a diabetic person
B)Insertion of the insuline gene in a mammalian
cell culture
C) insertion of the insulin gene in E.co;i
D)Insertion of the omsuline gene in a diabetic
person's pancrease cells
E) None of the above
 Answer D) Insertion of the omsuline gene in a
diabetic person's pancrease cells
Gene therapy is literally adding a functioning
gene into a patient that does not have a
functioning copy.

6. Advantages and Disadvantages of
Gene Therapy
The Pros:
 The most important factor in the development of gene
therapy is the fact that, for genetic disorders, there is
only one way of curing the disease – replacing the
defective gene with a healthy copy .
 If gene therapy targets the reproductive cells of
carriers of such genetic disorders as cystic fibrosis,
Parkinson’s disease, or cancer, it is possible that any
children the carrier goes on to have would be free of
the defective gene and on a bigger scale the disease
can be wiped out completely
 Gene therapy, when successful, can have a number
of advantages over drug therapy such as providing a
cure rather than easing the symptoms.

7. Disadvantages
 The current lack of knowledge and understanding of
the treatment means that its safety is unknown. The
current scientific understanding is based on theory
rather than solid fact
 In clinical trials already carried out the effects of the
treatment have only been short-lived. To achieve long
term results much more research is needed.
 Drug therapy, although not offering the possibility of a
cure, is a tried and tested method and is therefore
deemed safer
 With current knowledge there is no guarantee that the
vector carrying the healthy gene will end up in the
specific place it is intended – there is a risk of causing
even more damage to the genetic make-up that can
result in severe consequences for the patient

8. Medical Uses of Gene Therapy
 Gene therapy is being used in many ways. For
example, to:
 Replace missing or defective genes;
 Deliver genes that speed the destruction
of cancer cells;
 Supply genes that cause cancer cells to revert
back to normal cells;
 Deliver bacterial or viral genes as a form
of vaccination;
 Provide genes that promote or impede the growth
of new tissue; and;
 Deliver genes that stimulate the healing of
damaged tissue.

9. Agricultural uses

10. Ethical Issues raised of Gene
Therapy
Because gene therapy involves making changes to the body’s set of
basic instructions, it raises many unique ethical concerns. The ethical
questions surrounding gene therapy include:
 How can “good” and “bad” uses of gene therapy be distinguished?
 Who decides which traits are normal and which constitute a disability or
disorder?
 Will the high costs of gene therapy make it available only to the
wealthy?
 Could the widespread use of gene therapy make society less accepting
of people who are different?
 Should people be allowed to use gene therapy to enhance basic human
traits such as height, intelligence, or athletic ability?
 Current gene therapy research has focused on treating individuals by
targeting the therapy to body cells such as bone marrow or blood cells.
This type of gene therapy cannot be passed on to a person’s children.
Gene therapy could be targeted to egg and sperm cells (germ cells),
however, which would allow the inserted gene to be passed on to future
generations. This approach is known as germline gene therapy.
 The idea of germline gene therapy is controversial. While it could spare
future generations in a family from having a particular genetic disorder, it
might affect the development of a fetus in unexpected ways or have
long-term side effects that are not yet known. Because people who
would be affected by germline gene therapy are not yet born, they can’t
choose whether to have the treatment. Because of these ethical
concerns, the U.S. Government does not allow federal funds to be used