Scientists have discovered possible genetic risk factors involved in chronic fatigue syndrome (CFS), also known as myalgic encephalomyelitis (ME).
ME/CFS is a poorly understood condition that affects around 17 million people worldwide.
To better understand its cause, Steve Gardner at UK biotech firm PrecisionLife and his colleagues analysed DNA samples from 2382 participants of the UK Biobank study, who all had ME/CFS.
Most genetic studies look for differences in individual DNA letters, known as single nucleotide polymorphisms (SNPs). Gardner and his colleagues instead hunted for differences in combinations of SNPs, allowing them to identify genetic traits that may only be in a subgroup of people with ME/CFS.
The team identified 199 SNPs, of 14 genes, in 91 percent of the participants with ME/CFS.
A statistical analysis suggests this wasn’t a chance finding.
Previous studies have linked these genetic variants to our overall stress response, our circadian rhythm or body clock and the mitochondria that power our cells. People with these variants may also be at heightened risk of catching viral and bacterial infections or developing certain autoimmune conditions.
Research suggests that around 70 percent of people with ME/CFS report that their symptoms began after an infection. Many with the condition also commonly experience sleep disturbances and symptoms associated with autoimmune conditions, such as muscle and joint pain.
According to Gardner, identifying the genetic variants provides clues as to the underlying mechanisms of ME/CFS.
“These findings allow us to now target research towards these areas, which could significantly accelerate both the discovery of new diagnostics and provide a feasible background for novel drug discovery,” he says.
There are no diagnostic tests for ME/CFS, with people often told symptoms are psychosomatic.
Identifying these variants is insufficient to make a diagnostic test, as they indicate whether someone is at a heightened risk of ME/CFS, not that they have the condition, says Gardner. But they could point in the right direction.
“Knowing the genes allows us to see which processes are involved in the disease,” says Gardner. “We may be able to spot some of the products of those metabolic processes in the blood, which could help lead to a blood test or some other relatively non-invasive test.”
Chris Ponting at the University of Edinburgh, UK, says the findings could lead to new treatments, but warns that the study was relatively small for genetic research and the results need to be replicated.
Ponting is involved in the DecodeME study, which is analysing DNA samples from 25,000 people with ME/CFS. If the same 14 genes are identified, it could lead to work into blocking those pathways in tissues to help alleviate the symptoms of ME/CFS.
“If DecodeME were to find the same thing, it would really be quite exciting,” says Ponting.
“Knowing whether CFS is a disease of, say, mitochondria or the nervous system or an immune system disease, will be a huge step forward. At the moment, there’s a rather scattergun approach to looking at all things.”
