Human Gene Therapy

Gene therapy is a technique which has developed in the wake of recombinant DNA technology. It is a process that results in the changing of a genetic disorder by the adding a piece of DNA into the genetic material of a living cell. Thirty years ago this concept belonged to the realm of the human imagination made manifest in the works of science fiction. Today it belongs to the realm of the human imagination made manifest in the works of science. It is difficult to see the far reaching consequences of such a process, and even the short term effects are difficult to make a conclusion on. How is it affecting society? Who can benefit from its use? Should it be used at all? The answers are not simple to uncover, nor are they black and white, but an attempt at finding some solutions must be made. Before continuing, a basic understanding of the technical aspects of gene therapy is essential.

Technical Aspects

Although the highly technical aspects of human gene therapy are somewhat complex, the basic concept is very straight forward. The goal of gene therapy is to correct mistakes that have occurred within the genetic material of the living cell. Before being able to repair the damaged or defective genetic material, the location of the gene or genes causing the dysfunction in the individual must be determined.

Over the last fifty years or so, scientists have made a great amount of progress in this area, including the development of techniques which allow for the controlled manipulation and replication of specific segments of the human genome. These types of techniques have come to be known as recombinant DNA (rDNA) technology and have allowed scientists to analyze functions of genes which are not necessarily directly expressed at the phenotypic level. This is done by "cutting out" or excising a particular segment of DNA of interest from the genetic material of an individual and inserting it into a bacterial plasmid (a tiny ring of DNA in addition to the normal chromosomal material found within the cells of bacteria). The excising is done with the use of restriction enzymes, which are a group of molecules capable of "cutting" the DNA at specific points along its sequence of nucleotide pairs. By observing the end products of these gene inserts, scientists are able to determine the functions of the genes themselves and are therefore better able to analyze and understand the dysfunction of certain genes at the molecular level.

There are currently two types of gene therapy capable for human implementation. Germinal gene therapy consists of introducing new genetic material into the germ line cells (those cells from which the gametes are derived). This type of therapy affects not only the individual receiving the treatment but also has the ability to affect future generations through the gametes. Germinal gene therapy has not yet been executed on humans. Somatic gene therapy consists of introducing new genetic material into the cells of the body whose chromosomes will not be passed on to future generations. This type of therapy affects only the individual receiving the treatment, and has proved successful in treating human genetic disorders. The first use of somatic gene therapy on humans involved a young girl with adenosine deaminase deficiency (ADA), a rare immune -system disorder. She has been receiving treatment for this disease since the age of four, and is currently doing well at the age of nine. Since this pioneering effort, there have been many other instances of human implementation of gene therapy. In the December 14, 1995 issue of Nature, it was reported that 1024 individuals world-wide had undergone gene therapy trials.

Ethical Aspects

It is obvious that technological questions in this area are being answered very rapidly. However, the ethical questions that have arisen as a result of the technology are not being answered quite so readily. Until the development of this technology, people have had to deal with genetic inequality as a fact of life. With the advent of gene therapy, this may no longer be the case for some people. Most people feel that it is okay to use gene therapy to treat human genetic diseases. Somewhat surprisingly, even the Catholic Church has taken a stand for the use of gene therapy. Reverend Russell E. Smith, president of the Pope John XXIII Medical-Moral Research and Education Center, stated that gene therapy is "a very noble enterprise, because it is aimed at the actual cure of actual diseases." Some individuals, however, are concerned that the technique may be used for "treatment" of genetic "disorders" other than diseases. For example, in January of 1993, it was reported in USA Today that an 11 year old boy was receiving gene therapy treatments at a cost of $150,000 per year to increase his height. At 4' 11", four