Treatment that manipulates or alters genetic material within the deoxyribonucleic acid (DNA) structure of cells. At present, gene therapy for Parkinson’s holds great promise but is experimental. Current research is exploring ways to use gene therapy to stimulate natural production of dopamine and other brain chemicals involved in movement such as gamma-aminobutyric acid (GABA) and glial derived neurotrophic factor (GDNF).
One promising method of delivering altered genetic code to cell DNA involves using as a carrier a virus manipulated to be harmless (called an adeno-associated virus [AAV]). The virus “infects” the targeted cells, delivering the altered genetic material, which then replicates when the cells do. This is the same manner in which a viral “infection” spreads, but by manipulating the virus’s contents scientists create a beneficial rather than harmful payload. In this way, researchers hope, the new cells will eventually take over and will function normally, restoring neurotransmitter production and balance.
The first phase I clinical trials testing gene therapy in people with Parkinson’s began in the United States in October 2002. It is likely to be several years before researchers know whether the technique produces long-term or even permanent changes. Other gene therapy approaches are likely to target altering mutated genes such as the alpha-synuclein gene that are linked to Parkinson’s development, hoping to head off the disease before it gets started. Because gene therapy is in its infancy, scientists do not yet understand what risks, both short- and long-term, it poses for people.