Transcript Gene Therapy

Jordan Jones
Lauren Johnson
What is it?
 Gene therapy, also known as genetic modification, is a
technique for correcting faulty genes that are
responsible for developing diseases.
Why do it?
 Gene therapy is a form of treatment intended to
improve or cure a person of an otherwise untreatable
genetic abnormality that could hinder your lifestyle or
shorten his/her lifespan.
How do they do it?
 Scientists have found a way to alter viruses in a way
that allows them to carry normal genes into the
genome to replace faulty genes in a therapeutic
manner. They call these enhanced viruses “vectors”.
Types
 Somatic gene therapy – modifying the genetic make-
up of some of the cells or tissues of the person being
treated. This will only affect the patient, not his/her
offspring.
 Human Germline Genetic Modification (HGGM) –
modifying the patient’s sperm or egg cells so that the
modification will alter the genetic make-up of future
generations.
Techniques
 The most common approach is to insert a normal gene
into a nonspecific location in the genome to replace
the nonfunctional one.
 A nonfunctional gene can be swapped for a normal
one through homologous recombination.
 The nonfunctional gene can be repaired with selective
reverse mutation which returns a gene to its normal
function.
 Altering the regulation of a gene. (Changing the
degree to which it is turned on or off)
Why isn’t it more popular?
 Short-lived effects – Due to most cells short life span
and rapid division, it is difficult to maintain the
intended effect of the therapy. Multiple rounds of gene
therapy would be necessary.
 Immune response – Whenever a foreign substance is
introduced into the body and the immune system does
not recognize it as your own, it fights back. This means
that the therapeutic gene would be attacked and killed
before it could take effect.
Popularity, cont’d…
 Problems with viral vectors – Since the vessel of choice
is a virus it is a possibility that the virus could regain its
normal ability to cause disease.
 Multigene disorders – Most common genetic diseases
occur from a combination of defective genes. With
gene therapy, the operative candidates for treatment
are single-gene disorders because current techniques
are only able to target one gene at a time.