Human Gene Therapy :: Science Genetics Papers

Human Gene Therapy Gene therapy is the use of genes to treat disease. It represents a quantum leap in our approach to the treatment of human disease and will have a significant effect on medicine over the next ten years. William French Anderson, Michael Biase, and Ken Culver performed the first successful gene therapy on a human in 1990. They developed a protocol for treating Adenosine deaminase (ADA) deficiency, severe combined immune deficiency, also known as the" Boy in the Bubble disease". ADA deficiency is a result of inheriting two copies of the defective ADA gene (in other words it is a recessive disease). Possession of a normal gene leads to the continuous, regular production of ADA in cells throughout the body. Without at least one properly functioning gene, children have no way of converting deoxyadenosine (a waste product) into inosine. This leads to the rapid build up deoxyadenosine in the system, which becomes phosphoralysed into a toxic triphosphate which kills T-cell. The result is an al most complete failure of the immune system and early death. Concept of Gene Therapy The term gene therapy originally referred to proposed treatments of genetic disorders that would involve replacing a defective gene with its normal counterpart Current usage of the term now extends to include all treatments in which there is an introduction of genetic material into body cells to treat a variety of diseases. Gene therapy utilizes two theoretically possible approaches: 1) Somatic gene therapy entails the transfer of a gene or genes into body cells other than germ (egg or sperm) cells with effect only on the patient. The new genetic material cannot be passed on to offspring. Examples of Somatic gene therapy have already proven to be clinically effective. The first successful treatments of adenosine deaminase deficiency took place in 1990 in 1991 with two patients aged 4 and 11. Both are thriving with continuing treatment. The first successful treatment of familial hypercholesterolemia, a genetic condition, which affects the livers regulation of cholestrols in the blood, took place in 1992 of a 29-year-old woman. Her improvement was stable for the 18 months of the study and liver biopsy demonstrated activity of the inserted gene and no discernible abnormalities. Five patients have been treated as of 1994.Current research involving Somatic gene therapy is focusing on a number of areas. Clinical trials are being performed on a treatment for cystic fibr osis, a chronic genetic disorder.