With Hope Comes Risk

With hope comes risk

By Jordan Hills, Edmonton JournalMarch 26, 2012

Re: "Clinical trials give hope to sufferers of rare eye disease," the Journal, March 6.

Choroideremia is a rare genetic retinal degenerative eye disease primarily affecting the male population, causing progressive loss of peripheral vision and eventually leading to blindness.

The University of Alberta's departments of medical genetics and ophthalmology have received funding for the first retinal degenerative disease gene therapy clinical trial in Canada.

Halting vision loss, restoring vision and developing a cure are exciting possibilities that these clinical trials provide. This article describes the potential positive results, but fails to address the possible downsides, failures or ethical issues of gene therapy.

Gene therapy is the process of replacing a mutated gene with a normal, functioning copy in human cells.

Jessie Gelsinger died at age 18 in September 1999 while participating in gene therapy clinical trials. He suffered from ornithine transcarbamylase deficiency and died of a massive immune response brought on by the viral vector used to deliver the therapeutic gene. Since then, stricter safety measures have been implemented.

Leber's congenital amaurosis, an inherited retinal degenerative disease causing severe vision loss in early infancy, is an example of success in gene therapy. Maguire et al (2008) observed significant visual improvement following therapy.

While this has proved successful, we need to anticipate a realistic outcome as clinical trials are experimental; halting the progression of vision loss by providing a functional gene to sustain retinal cells is a reasonable expectation, while vision recovery or a cure is not.

If successful, gene therapy could be used to treat this disease early, before vision loss becomes substantial, to prevent further loss from occurring.

Approval and funding for gene therapy at the University of Alberta is an extremely exciting opportunity and patients should be optimistic.

However, discussing the possibility of a cure or correction of lost vision offers false hope and increases the chance for letdown if this does not occur.

Jordan Hills, molecular genetics student, University of Alberta, Legal