Scientists have identified a gene which causes some cases of Parkinson's Disease.
Parkinson's is a neurological disease
The findings could open up new avenues of research into other genetic factors which cause or predispose people to develop the disease.
Researchers at London's Institute of Neurology say in Science that they could also lead to new treatments.
Parkinson's is a degenerative, neurological condition for which there is currently no cure.
It is not generally a genetic condition, but there are some cases where it does run in families.
This is the first time a Parkinson's gene has been identified by researchers in the UK.
Professor Wood's team studied three families from Italy and Spain which had several members with the disease.
Researchers already knew that the fault lay somewhere on chromosome one.
When they analysed DNA from the families, they discovered mutations in the PINK gene which provides coded instructions for a protein which affects chemical reactions within cells.
It is hoped that understanding more about the gene, the protein, and what happens in the cells might lead to research into other genetic factors which affect people's chances of developing Parkinson's.
Professor Nicholas Wood told BBC News Online: "Any clues we can get about the causes of Parkinson's are good news.
"This finding could potentially lead to new drugs."
"The fact that the gene behaves in a way not even considered before opens up completely new avenues for research."
He added: "The next phase will be to look at how this gene operates normally and compare it to how it behaves when it is in the mutant form responsible for a person's Parkinson's.
"When this has been established other possibilities of researching new therapies to deal with the new and different cell activity can be tackled."
Linda Kelly, chief executive of the Parkinson's Disease Society said: "We are very excited about the results of Professor Wood's research.
"However, we are still only in the very early stages. It must also be stressed that this does not indicate that Parkinson's is a widely hereditary condition."