Gene Therapy in Dogs

Introducing normal genes into cells to replace defective genes that are causing disease or disorder is referred to as gene therapy. This therapy has been explored for use in humans and has been tested on dogs. It has potential to be part of veterinary treatment for diseases and disorders that are caused by, or contributed to, by abnormal gene sequences. In order to be effective, the nucleic acid material, genes, introduced into a cell, need to be delivered to a sufficient number of cells, and expressed for a sufficient length of time. This requires a vector for the nucleic acid to be inserted into the affected cells. A virus is usually used to accomplish this. Studies have been successfully completed in dogs using gene therapy to treat dystrophic muscle disease and retinitis pigmentosa. It is hoped that other diseases with genetic components including cancers may be successfully treated with gene therapy as more is learned. As this is a new therapy it will not be available at many veterinary clinics, but is available at some veterinary universities, and may become more widely available as the therapy is further developed.

Prior to gene therapy, an immune system suppressing drug will need to be administered for a short period of time, so that when the virus containing the gene to be inserted in targeted cells is administered your dog's immune system does not destroy the gene-containing vector. In studies conducted, the viral vector used to deliver nucleic acid was the viral vector AAV-9. AAV is a useful vector because it infects cells but does not cause illness.The virus was injected into the dog's blood stream or into the eyes, for retinal pigmentosa.

This resulted in the healthy proteins, mediated by the injected proteins, being detected in the dog’s tissues for several months after treatment, resulting in a decrease in illness.

Effectiveness of gene therapy depends on the ability to insert healthy gene sequences into a widespread number of cells for an appropriate length of time. Clinical trials with the virus AAV have shown some success at accomplishing this. AAV does not cause illness in the cells of infected animals, but is able to infect the affected cells with the required gene sequence nucleic acids. The use of gene therapy in dogs and other animals is at a very early stage and shows great promise for treating a wide variety of genetically mediated diseases and disorders.

Side effects of gene therapy do not appear to be significant. Multiple treatments may be required in order to ensure that the required gene sequences are present in affected cells in order to counteract unhealthy gene sequences present in the animal. Observation of your pet after treatment is important as the effects of gene therapy are not well-known and any side effects should be reported to your veterinarian.

As this is a new treatment, the cost of gene therapy has not been established. It is currently in a research and testing phase, but shows great promise to be a cost-effective therapy for serious diseases with genetic components.

Therapy is not widely available as it is still being developed and may not be accessible for many pet owners. Also the long-term effectiveness and side effects of gene therapy have not yet been established.

Gene therapy is a treatment for diseases with genetic causes and contributions. There are limited options for preventing such diseases. It is important to obtain dogs from reputable breeders that make the utmost effort to prevent and eliminate genetic disorders in their breeding program.