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?

 

April 2009