There is no current cure for the fusing of the spine in a bent position
Two genes that have a strong connection to a spine-fusing type of arthritis have been identified by scientists.
Ankylosing Spondylitis (AS) can lead to people becoming fixed in a bent position looking at their feet.
The two genes are involved in inflammatory processes in the body and could help the development of a treatment for the condition.
A charity said the findings of the experts at Oxford, the US and Australia were "a long-awaited breakthrough".
Current treatments only relieve the symptoms of the disease with physiotherapy and painkillers although some patients are being given an antibody treatment which costs £10,000 a year.
An international consortium of scientists led by Oxford University, the University of Queensland and the University of Texas, carried out a genome-wide study of 2,053 people with AS and 5,140 matched controls.
The study, published in Nature Genetics, found six regions of the genome that were associated with AS - the two strongest associations were with genes called ERAP1 and IL23R.
ERAP1 is involved in important pathways in the body that are thought to have roles in controlling inflammation.
IL23R has also been implicated in psoriasis and inflammatory bowel disease, other conditions that also involve inappropriate inflammatory responses.
Lead researcher Professor Paul Wordsworth said: "We knew there was a strong genetic component to this disease, and we now have the foundation we need for future research to pin down the genetic causes of this condition.
"Cheaper or curative alternatives are a pressing need for this debilitating disease."
AS is an inflammatory type of arthritis that affects up to 200,000 people in the UK and is a significant cause of work-related disability
It typically starts to cause problems for people in their 20s
It affects the spine, resulting in progressive stiffness, loss of movement and pain as the disease develops
It affects the spine, resulting in progressive stiffness, loss of movement and pain as the disease develops.
Treatment involves physiotherapy and pain killers and some sufferers are being given new antibody therapies that are effective in suppressing the symptoms but cost around £10,000 per year
Professor Alan Silman, medical director of the Arthritis Research Campaign, which co-funded the research, said the discovery of the six new genetic regions in AS was a long-awaited breakthrough in genetics research.
He said: "There are many theories as to what triggers this condition but understanding which genes are involved is a major step forward which could lead both to new treatments but especially earlier diagnosis, which is badly needed in ankylosing spondylitis.
"Some patients can wait up to a decade to be properly diagnosed."
Professor Silman said the research had only been enabled by available new technology which had allowed the investigation of such a large number of genes.