The uses

Gene therapy research and trials are being conducted to treat conditions such as:

Mending a broken heart

Heart attacks cause damage to the muscle cells of the heart. Scar tissue forms , disrupting the heart's electrical system, and weakening the heart.

Recently, researchers have reprogrammed the scar tissue, making it behave like heart muscle cells.

The researchers, from the Children's Medical Research Institute (CMRI) in Sydney and the Children's Hospital Westmead, added two extra genes to the scar tissue cells. One gene programs the cell to be excitable, like a muscle cell, and the other allows the cells to communicate, passing on the electrical pulse of the heart.

 

Gene therapy trials

In 1990, four-year-old American Ashanthi DeSilva became the first person to be treated with gene therapy for severe combined immunodeficiency (SCID) syndrome. Because this disease affects the immune system, children born with it are very susceptible to any infectious diseases, and must be kept in germ-free environments such as a plastic enclosure. SCID is therefore sometimes referred to as 'boy in the bubble' syndrome.

Ashanthi's cells were provided with genes encoding an infection-fighting enzyme that she lacked. Doctors removed white blood cells from her body, grew the cells in the lab, and inserted the missing gene into the cells using a viral vector. The genetically modified blood cells were then infused into her bloodstream.

This procedure is not a cure. The treated white blood cells only work for a few months, and the process must be continually repeated. Since that trial, more than 3000 people have received this treatment in human clinical trials.

Gene therapy is still an experimental procedure, and has suffered a number of major setbacks since this first trial. Some trial patients developed a leukaemia-like illness caused by the vector used to transfer the gene. Trials were temporarily halted to allow time for the development of safer gene transfer vectors, and are now underway again in several countries. Future techniques may be safer, and be able to deliver the correct gene, to the correct cells, in the correct tissues.

A 2007 gene therapy trial for inherited retinal disease had promising results. Patients had a modest increase in vision with no apparent side-effects.

The NHMRC is in the process of establishing an expert Cellular Therapies Advisory Committee to provide medical and technical advice to Human Research Ethics Committees on the clinical application of gene therapy. http://nhmrc.gov.au/about/committees/expert/ctac/index.htm