Gene Therapy

There are many obstacles and ethical questions concerning gene therapy. For example, some retrovirusal vectors, can also enter normal cells and interfere with the natural biological processes, possibly leading to other diseases. Other viral vectors, like the adenoviruses, are often recognized and destroyed by the immune system so their therapeutic effects are short-lived. One of the primary limitations in gene therapy is that delivering a gene using a viral vector that can only undergo one round of infection (making it safer) may provide only temporary therapeutic value that lasts only as long as the corrected gene is expressed. As a result, some therapies need to be repeated often to provide long-lasting benefits.

One of the most pressing issues, however, involves gene regulation. Several genes may play a role in turning other genes on and off. For example, certain genes work together to stimulate cell division and growth, but if these are not regulated, the inserted genes could cause unregulated cell growth leading to the formation of a tumor. Another difficulty is learning how to make the gene be expressed in a regulated way. A specific gene should turn on, for example, when certain levels of a protein or enzyme are not sufficiently meeting cellular demands. This type of controlled regulation of gene expression for these delivered genes is very difficult to achieve.