What is Human Gene Therapy

Human gene therapy is a milestone in the field of medical science, applicable for treatment of chronic health conditions and genetic disorders. However, there are certain factors related to the effectiveness of gene therapy techniques such as autoimmune responses, vectors, multigene disorders...

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A gene is a stretch of DNA (deoxyribonucleic acid) that contains nucleotide sequences. ****d on the nucleotide sequences, specific proteins are synthesized, which in turn, are responsible for expression and function of body cells and tissues. If there is any alteration in the genetic sequence, the protein synthesis is disturbed. In such a condition, the cells and tissues are unable to perform their normal function, leading to genetic diseases.

What is Human Gene Therapy

Human gene therapy is a scientific technique, by which a segment of nucleotide sequence or gene is inserted into an individual's cell for the purpose of treating diseases. The main principle behind gene therapy is to restore the normal functioning of cells and tissues by replacing abnormal or mutated genes. In simple terms, it is a method of correcting defective genes. There are several ways of implementing gene therapy; inserting a normal gene in the genome to replace a defective gene and changing the regulation for expression of a specific gene. Another method of gene therapy is to apply selective reverse mutation so that the defective gene returns to its original form.

In majority of human gene therapy cases, a normal therapeutic gene is inserted by using a vector or a carrier molecule. As the name suggests, the vector serves the purpose of delivering the normal gene to the target cell. As the vector incorporates the therapeutic gene in the target cell (for example liver cells), the therapeutic gene starts producing functional proteins, thus restoring the normal function of the target cell. While speaking about the vector or carrier molecule, various types of viruses such as retrovirus and adenovirus are used for the purpose. Before using any of these viruses as vectors, the genomic content is changed by removing disease-causing gene and replacing it with therapeutic gene.

Pros and Cons of Human Gene Therapy

There are many potential side effects of using viruses as vectors, some of which include target-related problems, inflammatory response of the immune system and at times, toxicity. A more recent technique of human gene therapy is to introduce the normal gene directly to the target cell without using vectors. Though this method sounds comparatively easy, it is not applicable to all types of target cells. Another disadvantage of this method is that it requires large amount of DNA.

A major drawback of gene therapy is the short-term effectiveness of the therapeutic gene after introducing into the target cell. It is the dividing cells present in the body that prevents the expression of therapeutic genes. After inserting the foreign therapeutic gene into the target cell, it is necessary to regulate the autoimmune responses of the body. Human gene therapy is less effective for multigene problems (presence of many defective genes).

Though the technology of human gene therapy is not so advanced in the present scenario, it has already widened the scope of medical science. As all genetic disorders and most of the chronic diseases involve malfunctioning of the genes, gene therapy is a promising technique for treatment of such severe health conditions. Genetic researches ****d on human gene therapy are ongoing to discover treatment options for chronic medical conditions such as heart disease, cancer, cystic fibrosis and AIDS. Nowadays, private grants as well as government grants are provided so as to encourage studies on human gene therapy.

From: http://www.buzzle.com/articles/what-...e-therapy.html