re for thalassemia is bone marrow transplantation, this masking of the defective gene splicing site offers a much needed treatment. It is also a better treatment than trying to replace the gene, which has been done in the past, because that results in excess RNA and hemoglobin production, which also causes problems.
Adenoviruses have long been used as vectors in gene therapy, but they do not last for ever in the body, and multiple doses are not possible because the immune system develops resistance to them (1:24). Work is now being done on an adenovirus transposon vector that can stabilize transgene expression over time. In vitro, stability has been achieved for six months or more. It has also worked in the mouse model. This technology promises to make one-time application of the therapy last a lifetime.
ParkinsonÆs disease occurs because of a profound loss of a specific type of nerve cell which lies deep in the brain and produces dopamine, a neurotransmitter (2:4). A reduction in dopamine levels leads to a loss of control of movement caused by a disturbance in the brain mechanism which normally controls it. This causes overactivity in the subthalamic nucleus (STN) in ParkinsonÆs patients. Researchers have developed a form of gene therapy in which an adenovirus vector with an inserted GAD gene is delivered to the affected brain area, where it produces small molecules of GABA. The release of GABA from the nerve cells inhibits the overactivity in the STN region of the brain, and so normal movement control is possible in these patients.
After successful tests in rats and primates, in which normal motor control was achieved with no negative side effects, the FDA has approved tests in humans (2:4). The gene therapy i
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