Gene Therapy Pros and Cons

"BLASPHEMY!" some cried when the concept of gene therapy first surfaced. For them tinkering with the genetic constitution of human beings was equivalent to playing God, and this they perceived as being sacrilegious! On the other side was the scientific community, abuzz with excitement at the prospect of being able to wipe certain genetic disorders in humans entirely from the human gene pool. Although the term gene therapy was first introduced during the 1980s, the controversy about the rationality of this line of treatment still rages on. In the center of the debate lie the gene therapy pros and cons that derive opinions from religious, ethical and undoubtedly, political domains.

What is Gene Therapy?

Put in simple words, gene therapy is substituting defective genes in a cell with the correct ones. Genes are the basis of heredity. The are made of triplets of nitrogenous bases that code for amino acids. The amino acids make up proteins that play important role in the way our body functions. Hence, defective genes result in malfunctioning metabolic pathways that manifest as diseases, the causes of which are embedded deep within our genetic makeup. Hence, till date there is no cure for genetic disorders. Treatment is only symptomatic. No wonder there is so much frenzy in the scientific community about the therapeutic effects of gene therapy. Read more on what is human gene therapy.

Gene Therapy Treatment

Gene therapy can be broadly classified into two types. One is the somatic cell gene therapy and the other is the reproductive cell or germline gene therapy. In somatic cell gene therapy, the somatic cells are targeted for gene replacement, whereas in the reproductive cell gene therapy, the defective gene lies in the reproductive cells that are replaced by the correct gene. The alterations made in the genetic makeup of the somatic cells is corrective only for the patient. This change is not inherited by the treated person's offspring. However, in case of germline gene therapy, the changes are passed on to the descendants of the treated individual. Hence, this line of treatment has the potential of altering the human gene pool for good. Read more on understanding genes.

How is Gene Therapy Done?

Gene therapy depends upon vectors, that is carriers of the normal genes that transfer them to the cells that have the defective gene. One of the most popular vectors are virus, most popularly retroviruses that have the capability of injecting their genetic material into the host cells. This viral genetic material is armed with the correct gene and once it integrates with the host genome, all the cells resulting from cell division of the host cell will contain the copy of the correct gene in place of the defective one. Liposomes, adeno-viruses and using naked DNA are some other options for vectors that are being investigated to replace defective genes in organisms.

Read more on:

• Human Genetics
• Genetic Engineering

Gene Therapy Pros and Cons

In order to be able to appreciate people's concerns about gene therapy we need to first understand the pros and cons of gene therapy.

Gene Therapy Pros

The single most factor that gives gene therapy its edge is its incredible therapeutic potential. The human race has always been under the continuous onslaught of diseases. As we find cure for some of the diseases, we are attacked by new and more virulent forms of germs. Although such diseases can be cured through medicines, genetic disorders have no cure unless the defective gene is replaced by the correct one and this is what gene therapy aims at. Moreover, by targeting the reproductive cells, such defects can be got rid of for good. People suffering from genetic disorders like Parkinson's disease, Alzheimer's disease and Huntington's disease are some of those whose only hope for cure is gene therapy.

Gene Therapy Cons

Scientific Issues: Although the most popular choice as a vector, using virus for the purpose is not foolproof. There is a specific point within the host genome where the correct gene should be introduced. There is no guarantee that the viral enzyme that is responsible for this step will be able to introduce the correct gene at the specific point in the host chromosome. In case, there is an error in this process, it would result in error in the genetic makeup of the cell and can result in serious disorders.

Moreover, the body's immune system may destroy the vector as it may perceive the carrier as a foreign body. Then there are problems with introducing therapeutic DNA and the rapidly dividing nature of certain cells that are hurdles in gene therapy providing long term benefits to patients. Due to this reason a patient may need to undergo multiple gene therapy treatments. But with this again comes the problem of the immune system. Once the immune system is triggered by a foreign body, it attacks the foreign body more aggressively when it invades the body next time.

Ethical Issues: Given the technology involved, it is obvious that gene therapy treatment will be expensive. It will be just the rich who would be able to afford its benefits. This gives rise to the refrain that gene therapy will make the rich, richer and the poor, poorer.

We know the potential of reproductive gene therapy. The scope of this line of treatment triggers the fear of eugenics - a term that denotes creation of a superior race, the idea that media has tried to embody in the concept of designer babies. Although this definitely isn't on the minds of geneticists but it is difficult to erase the repercussions of Hitler's belief in supremacy of the Aryan race. Read more on ethics of human gene therapy.

Religious Issues: Manipulating genetic makeup of man is absolutely unacceptable by those with strong religious beliefs. According to them altering genes is similar to tinkering with nature. It's like questioning God's will or in other words, 'playing God'.

Undoubtedly, the therapeutic advantage of gene therapy is a blessing for mankind. However, unless the techniques of gene therapy are perfected, gene therapy pros and cons will keep fueling the controversy. But should we deny mankind the blessings of a revolutionary scientific development that would bring an end to numerous incurable diseases? Be it industrialization or its harmful effects or the awesome source of power that nuclear energy is or its ugly face that we saw during the Hiroshima and Nagasaki bombings, man has been walking the tight rope of scientific developments and its ill effects. Would gene therapy then be too much for us to handle? I leave this question for you to answer.