Parkinson’s disease (PD), a severely crippling disease of the nerves and brain has been linked to genes that affect the immune system according to new research. In these patients the immune system may go awry attacking healthy tissues or failing to fight infections that leave people susceptible to the condition scientists say.
PD causes a steady dying of brain cells that produce a chemical called dopamine. In the United States, 50-60,000 new cases of PD are diagnosed each year, adding to the one million people who currently have the condition, which causes tremors and difficulty with movement and ultimately total immobility. Researchers have also looked at clinical, genetic and environmental factors that might contribute to the development and progression of Parkinson's disease and its complications.
Cyrus Zabetian, a co-author on the study and neurologist at the University of Washington in Seattle said, “People have speculated about a link between the immune system and Parkinson's disease for some time and this study suggests that the link is real.” The study was led by Haydeh Payami, a professor of genetics at New York State’s Wadsworth centre.
The team compared the genetic make-up of 2,000 patients with late-onset Parkinson's disease and 1,986 healthy volunteers. They found four genetic mutations that were more common in the patients than the control group. Three of the mutations are already known to raise the risk of Parkinson's disease, but the fourth had not been linked to the condition before. This newly discovered mutation lies in the human leukocyte antigen region or HLA, which contains a large number of genes related to immune system function. Researchers believe that this finding also explains why drugs that suppress the immune system, like ibuprofen, appear to protect against Parkinson's disease. Nicotine and caffeine are also thought to delay the onset of the disease.
According to Kieran Breen, director of research at Parkinson's UK, “Previous studies have shown that inflammation does occur in the brains of people with Parkinson's, but identifying the potential factors that may lead to the death of nerve cells has been difficult…We know already that some people are more susceptible to getting Parkinson's due to their genetic makeup. This study also points to some genes that may be involved.”
Dr. Payami believes that this finding could mean newer and better treatment for PD. The study is published in the journal, Nature Genetics. The study was funded in part by the National Institute of Neurological Disorders and Stroke, one of the National Institutes of Health.