Genes are inherited biochemical messages that shape the body and direct its functions. Genes usually have four molecules that make up DNA, arranged in seemingly infinite combinations. 1 There are between 50,000 and 150,000 genes in the body, and 1014 cells. 2 Because the arrangement and presence of each gene is vital to proper function, the absence or insufficiency of a single gene can cause such diseases and inherited disorders as severe combined immunodeficiency, Leber congenital amaurosis, hemophilia, sickle cell disease, ornithine transcarbamylase deficiency, and certain cancers. Gene therapy is based on the replacement or repair of the faulty gene. Although there have been studies on the efficacy of gene therapy in each of these diseases, as well as in AIDS, and there has definitely been success, tragic fatalities like that of Jesse Gelsinger, and faults revealed in methods cause gene therapy to be questionable in safety. However, it is on its way from being a science fiction fantasy to a reality of medicine.

Gene therapy was first developed mainly as a treatment for inherited diseases, ideal models for gene therapy because they are usually caused by the deficiency of a single gene and lack effective treatments. 2 its efficiency is based on the supposition that most diseases can be traced back to genes. The basic concept of gene manipulation to achieve therapeutic results was outlined formally in 1972 in an article, “Gene Therapy for Human Disease?” by Theodore Friedmann and another scientist. This proposed the use of artificial viruses to insert beneficial genes in the same manner that actual viruses insert their own DNA to force a cell for work for it. 1 In the past decade, gene therapy has been tested in over 350 trials in solely the United States, enrolling 4000 subjects. 3 It would sometimes appear that success is extremely limited, particularly in light of the death of a young participant in a gene therapy study for ornithine transcarbamylase deficiency. However, quickly following what may have been a fatal blow for gene therapy, was the successful treatment of two infants in France, curing them of severe combined immunodeficiency (SCID). SCID leaves the bodies’ immune system defenseless; the disease is also called “bubble boy disease”. Even a slight infection could destroy the afflicted person. 4 In May 2000, two infants were cured via delivery of the missing gene with a modified virus, the effects of which were seen within two weeks. This seemed to be the first authentic breakthrough for gene therapy. Doctors previously treated many young SCID patients successfully with bone-marrow transplants, but the two infants were the first successful gene therapy patients, and gene therapy is now being studied further to test for its use as a permanent treatment for SCID. 4 Gene therapy success was also seen in its use as a treatment for hemophilia, which causes a person to bleed profusely, often spontaneously in joints up to 30 times a year. It is caused the mutation of a gene that leaves the person bereft of a protein necessary for proper blood clotting.