By Fiona Macrae
A simple blood test could revolutionise the treatment of arthritis for hundreds of thousands of sufferers. British and Irish scientists have identified a gene that is linked to rheumatoid arthritis – especially in severe forms of the disease.
If patients were tested early on to see if they had the gene, they could then receive more targeted treatment and be fast-tracked for the most powerful medications.
The breakthrough also paves the way for new drugs.
Rheumatoid arthritis, which is one of the most common forms of the disease, occurs when the immune system attacks the joints by mistake, causing painful inflammation and stiffness.
The wrists, fingers, toes, ankles and knees are particularly susceptible, and some 400,000 Britons are affected.
Current drugs, which merely tackle the symptoms, do not work for everyone.
By studying samples from more than 1,000 Britons, the researchers from the University of Sheffield and University College Dublin showed that a gene called C5orf30 is key to rheumatoid arthritis.
A flawed version of the gene was found in those with the condition, but not in those with other forms of arthritis or in healthy people.
The rogue gene was particularly strongly linked to severe forms of the disease, in which a sufferer’s health deteriorated rapidly, the journal Proceedings of the National Academy of Sciences reports.
In future, patients could be given a simple blood test when they are first diagnosed with arthritis.
This could help doctors work out the most suitable drug to give to different patients.
Those thought to be most at risk could also receive more powerful drugs usually reserved for later in the course of the disease, which could delay the progression of their illness and greatly improve their quality of life.
Jane Tadman, of Arthritis Research UK, said: ‘For us and other research bodies, identifying blood or tissue markers that help to target the right drug to the right patient at the right time – so-called stratified or personalised medicine – is a priority area and something we are investing in heavily.
‘The new findings from this group could take us a step closer to that goal, so that patients can be given drugs we know will work for them early in their disease that will prevent or minimise joint damage.’
The study also showed that people with severe rheumatoid arthritis had very low levels of a protein made by the C5orf30 gene in their joints. This suggests that raising levels could help protect the joints.
Sheffield researcher Dr Munitta Muthana said that, in the same way as diabetics are given insulin, people with rheumatoid arthritis could be given a top-up of the protein. However, more research is needed.
John Church, of Arthritis Ireland, which part-funded the study, said: ‘The outlook for a person diagnosed with arthritis in 2015 is much brighter than it used to be.’
Rheumatoid arthritis, which is three times more common in women than men, can cause such fatigue and disability that half of sufferers give up work within ten years of diagnosis. It also increases the risk of other conditions, including heart and lung disease.
Other scientists are trying to treat the condition by bypassing drugs entirely, instead using a pacemaker-style implant to target the nervous system.
They found that by firing impulses, the implant made the spleen produce fewer chemicals that cause the inflammation in the joints.