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Human gene therapy, what doesn’t kill us will only make us stronger.
Warren Hochfeld
While genetically modified foods are proving increasingly controversial, the
path towards genetically modifying humans is perhaps in great demand.
The recently completed mapping of the human genome and years of genetic
engineering research drives its progress. Our genes are part of make us unique,
inherited from our parents, they form the blueprints for our physical traits.
Expression of these genes results in the production of proteins, which serve as
the building blocks for tissues as well as the regulators of chemical reactions
taking place inside all living cells. Mutations or changes in any one of these
genes can result in diseases, physical disabilities, or even a shortened life
span.
Ordinary medicine can only moderate symptoms of genetic diseases and
treatments are typically only temporary. Gene therapy has the potential to
eliminate the root causes of certain diseases by repairing or modifying the
patient’s genetic code. Conceptually, if you consider the world only at the
molecular level, gene therapy is a logical, straightforward solution to genetic
disease: if a gene seems to be causing a disease, then to cure the disease
scientists must remove the “bad” gene, and substitute or add a “good” gene.
The theoretical advantages of gene therapy are undisputable, however, thus
far gene therapy has not delivered on its promised results: nearly 1,000
clinical trials of gene therapy have been conducted worldwide since the early
1990s and only a small number of these trials have resulted in therapeutic
benefit to patients. Inflated expectations and dismal results are fuelling false
hopes among those who truly suffer, which makes it difficult for this
controversial therapy to earn the crucial support among the public and within
the government. Critics point to its non-therapeutic enhancement possibilities,
the potential for eugenic social policies, and a spotty safety record that has
resulted in deaths of subjects undergoing treatments.
In an ideal scenario of gene therapy, the cell with the corrected DNA will
multiply, producing more copies of the corrected gene, thus freeing the body of
the genetic abnormality and curing the disease. However significant problems
remain in all basic aspects of gene therapy. Major difficulties at the basic
level include shortcomings in all current gene transfer vectors and an
inadequate understanding of the biological interaction of these vectors with the
host. The theoretical foundations underpinning its success are in place, but
science as always is more difficult in practice. The correcting gene can
potentially be inserted into the wrong cell type, or be expressed
inappropriately, either in the wrong amount or at the wrong time during
development, therefore disrupting another gene or its means of control.
This might initiate a new genetic disease, or perhaps an uncontrollable
multiplication of cells which could lead to cancer. For example, in cases of
Severe Combined Immunodeficiency (SCID), researchers were able to genetically
modify doses of patients own white blood cells to correct a defective gene. It
was reported in The Journal of Science that since the trials began in 1999, gene
therapy has resulted in the restored immune systems of 17 children, while three
children developed leukaemia and one died.
While scientists, doctors and medical professionals seek ready made cure-alls
during this developmental stage in gene therapy, opinions will arise. Regardless
of enthusiastic optimism or scathing criticism, gene therapy holds enormous
promise for eliminating inherited illnesses, replacing damaged tissue, and
ultimately curing diseases such as cancer, AIDS and diabetes. Biotechnology is
set to dramatically alter the way in which a human being is a being. Perhaps,
what doesn’t kill us will only make us stronger?
More information:
 Warren
Hochfeld holds an MSc and BCom from University of Pretoria and is currently
engaged in research towards his PhD at the Cambridge Institute of Medical
Genetics.
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