US researchers have identified a set of genetic changes commonly found in people with chronic fatigue syndrome (CFS), a poorly understood condition for which the exact causes remain unknown. The new research, organised by the Centers for Disease Control and Prevention (CDC) in Atlanta, suggests that CFS is actually a collection of five or more different conditions with varying genetic and environmental triggers. A series of studies, all published in the journal Pharmacogenomics, suggest that some people are born with a predisposition to the disease, involving key brain and immune system genes.
CFS, also known as myalgic encephalitis (ME), causes exhaustion, headaches, sleep and memory problems and, frequently, pain. The condition, which was first identified in the late 1980s, is often triggered by infection, injury or stress. The CDC took a multipronged approach to try and shed light on the biological basis of CFS, in a series of studies carried out by biologists, epidemiologists and mathematicians. The results, published in a set of 14 papers, show that CFS is 'a real bodily dysfunction', according to the scientists. 'The idea that these people are just tired is pretty clearly refuted by this batch of results', Ben Goertzel - one of the study leaders - told Nature News.
The CDC researchers identified 227 CFS patients living in Wichita, Kansas - recruited by telephone, since many affected people are never actually diagnosed with the illness. The team asked participants to come in for two days of tests, to collect data on their sleep patterns, memory and nervous systems. They also took blood samples, which they used to search for mutations in several genes previously linked to CFS. The scientists also measured the activity of a further 20,000 genes, using 'gene chips'. The study revealed that people with CFS have a 'hallmark' set of changes in 12 genes that are involved in the body's response to stress.
The scientists hope that the findings will lead to improvements in the understanding, diagnosis and treatment of CFS. They stress, however, that the studies will need to be repeated by other laboratories - work that could take decades. The CDC also hopes that the multidisciplinary approach taken in the research could help pinpoint the causes of other biologically complex conditions, such as autism.
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Chronic fatigue has genetic roots
Chronic fatigue may all be in the genes, US says