This week, a patient undergoing a gene therapy study in Seattle died from complications of the procedure, causing the government to suspend the study. The patient’s cause of death was not revealed. They were undergoing therapy for advanced arthritis. This is the third death since 1999 in the gene therapy field. Scientists do not know if the deaths are resulting from the viruses they are using to inject new genes into patients.

About 28 other gene therapy studies are also using this virus called adeno-associated virus or AAV. About 100 people had enrolled in Targeted Genetics Corp. without problems. The patient who died became sick after the second injection of the therapy directly into an arthritic joint. Other procedures used to help treat arthritis include drugs that block joint inflammation, but gene therapy is a rapidly growing approach. In 1999, an 18-year-old male died in his fourth day of treatment at the University of Pennsylvania. The only disease ever actually cured with this treatment is an immune disorder called severe combined immunodeficiency disorder or SCID. These patients often live their lives in plastic rooms to keep them from developing illnesses or infections that could kill them. However, those who are treated for this disease as infants often developed cancer later in life, a side effect believed to be linked to the virus.

There are several approaches taken in gene therapy. They include, replacing nonfunctional genes, swapping abnormal genes with new ones, repairing damaged genes, or regulating a gene that is turned on or off. These methods are sometimes done by infecting a patients liver or lung cells with a viral vector which unloads genetic material containing the normal human genes. There are also nonverbal approaches to gene therapy. One way is to directly introduce therapeutic DNA into target cells, but this can only be done with certain tissues and requires large amounts of DNA. Another approach is an artificial liquid sphere with an aqueous core which carries the DNA to the target cell’s membrane.

This therapy obviously comes with risks and side effects. First off, researchers must make sure that the genes remain functional so that patients don’t have to undergo continuous therapy. There are also immune response problems, problems with viral vectors, and multigene disorders still standing in the way of the success of this method of treatment. Those who undergo the treatment can end up with heart disease, high blood pressure, Alzheimer’s arthritis, and diabetes that result from the variations in genes. However, the only way to get this therapy right is to practice, and unfortunately that does not come without a price.

For related articles visit http://www.msnbc.msn.com/id/19983734/ and http://www.ornl.gov/sci/techresources/Human_Genome/medicine/genetherapy.shtml

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