0.4 About the controversal ethical issues on applications of  (Page 3/6)

The first human gene therapy protocol that successfully treated adenosine deaminase deficiency (ADA) disease began in September 1990.

From 1989 until September 1999 there were thousands of patients in trials, and no one died because of the experiments. Eighteen-year-old Jesse Gelsinger died at the University of Pennsylvania (USA) on 17 September 1999, four days after receiving a relatively high dose of an experimental gene therapy. His death was the result of a large immune reaction to the genetically engineered adenovirus that researchers had infused into his liver. There was much review of the procedures for safety following that case.

Gene therapy is still an experimental therapy, but if it is safe and effective, it may prove to be a better approach to therapy than many current therapies because gene therapy cures the cause of the disease rather than merely treating the symptoms of a disease. Also, many diseases are still incurable by other means, so the potential benefit is saving life.

Germ-line gene therapy

Preimplantation genetic disease diagnosis

In medicine and (clinical) genetics preimplantation genetic diagnosis (PGD) (also known as Embryo Screening) refers to procedures that are performed on embryos prior to implantation , sometimes even on oocytes prior to fertilization . PGD is considered an alternative to prenatal diagnosis . Its main advantage is that it avoids selective pregnancy termination as the method makes it highly likely that the baby will be free of the disease under consideration. PGD thus is an adjunct to assisted reproductive technology and requires in vitro fertilization (IVF) to obtain oocytes or embryos for evaluation.

The term preimplantation genetic screening (PGS) is used to denote procedures that do not look for a specific disease but use PGD techniques to identify embryos at risk. PGD is a poorly chosen phrase because, in medicine, to "diagnose" means to identify an illness or determine its cause. An oocyte or early-stage embryo has no symptoms of disease. The person is not ill. Rather, he may have a genetic condition that could lead to disease. To "screen" means to test for anatomical, physiological, or genetic conditions in the absence of symptoms of disease. So both PGD and PGS should be referred to as types of embryo screening.

Ethical issues