Figure 1. Gene Therapy Using an Adenovirus Vector
an unhealthy, dysfunctional gene. Usually these vectors are viruses, most commonly retroviruses or adenoviruses that have been modified to be used safely for the purposes of genetic transfer.6 Viruses are often used because they possess the unique ability to differentiate between different types of cells and insert the genetic material into specific cells.7 These viruses carry the healthy gene into the target cells that contain the dysfunctional gene and replace the dysfunctional gene with the code for the healthy gene that is located inside the body of the virus (Figure 1). This can happen several different ways. Some viruses, including the retrovirus, insert their own DNA along with the new gene directly into the chromosome, while other viruses, such as the adenovirus, merely insert the new gene into the cell’s nucleus.8 The virus then reproduces and spreads throughout the body, repeatedly infecting new cells with the modified healthy gene. Between the spread of the healthy gene by the virus and the natural reproduction of the now healthy9 genes, the human genome is slowly repaired. Here and now in the twenty first century, the FDA has not approved any gene therapy products for use by the general public.10 However, over the past twenty years the number of new gene therapy trials has steadily risen, and the number of publications relating to the field of gene therapy has skyrocketed.11 Perhaps best demonstrating the wide availability of the inner processes and workings of genetic manipulation are
a collection of books called the Springer Protocols that provide students and researchers with reproducible laboratory experiments and procedures pertaining to most life sciences. The volume most relevant to gene therapy is titled Transgenesis Techniques: Principles and Protocols and begins by saying “One of the major challenges currently facing the scientific community is to understand the function of the 20,000 to 25,000 protein-coding genes.… This book details the transgenic techniques that are currently used to modify the genome in order to extend our understanding of the in vivo function of these genes.”12 The book then goes on to provide 21 fully developed lab techniques directly involving or on the subject of genetic manipulation of model organisms such as flies, zebrafish and mice. With the increase in research and development of the medical science of gene therapy, there comes a need for the further discussion and dissection of the ethical issues concerned with pursuing this science and its application to humans. As gene therapy becomes more developed and is used to treat a greater number of patients, the most relevant ethical concern will become one of justice. There are several ethical concerns that fall under the category of justice, beginning with accessibility to treatment. The therapeutic procedures involved in gene therapy use some of the most modern medical technology available and, therefore, prove to be unbelievably expensive. Needless to say, when these treatments become approved for use by the general public, only the very upper financial class will be able to afford them. This 24