Research reported in a collection of 14 articles in the April 2006 issue of the journal Pharmacogenomics, has documented, for the first time, a genetic basis to chronic fatigue syndrome (CFS) - also known as ME or post-viral fatigue syndrome.

The series of papers, produced by the US Centers for Disease Control (CDC), presents an analysis of the most detailed and comprehensive
clinical study ever carried out on CFS.

The study itself involved a meticulously thorough investigation of 227 adults, including non-fatigued 'controls' for comparison, as well as CFS patients. During two days spent on a hospital ward, the volunteers underwent detailed clinical evaluations - measurement of sleep physiology, cognitive function, autonomic nervous system function and extensive blood and urine tests as well as psychiatric evaluation and assessment of their medications. Perhaps most importantly, an assay was also carried out of the activity of 20,000 genes, in the hope of identifying factors that potentially cause or are related to CFS.

Genetic predisposition

The resulting data included 500 clinical measures and details of the 20,000 measures of gene expression (the process by which genes regulate cell activity). The data was independently examined by four specially assembled teams of investigators that included medical experts, molecular biologists, epidemiologists, physicists,
mathematicians and engineers.

The results showed that people with CFS have specific genes and gene activity patterns that render their bodies unable to adapt to the
challenges and stresses encountered throughout life, such as infections, injury, trauma, and other adverse events. Chronic fatigue patients were, for example, twice as likely as controls to have high levels of 'allostatic load', which is a measure of stress hormone secretions, blood pressure and other signs of wear and tear on the body.

Also of significance is the finding that there are at least five subtypes of CFS, classified according to criteria that include their genetics and the way that their symptoms unfold.

A biological basis

The creation of a molecular profile of individuals with CFS has been hailed as a very important step forward. Knowing that there is a biological basis for CFS will help researchers identify more effective ways to diagnose the illness (currently diagnosed on symptoms, in the absence of evidence of particular alterations in the body or from blood tests) and should assist in producing more effective treatments.

Moreover, no doctor should ever again dismiss ME/CFS as 'all in the mind'.

The US Centers for Disease Control are a division of the US Department of Health and Human Services, the principal US agency for protecting the health and safety of the nation. The fact that this study emanates from this particular source adds credibility to its findings. However, this work does need to be replicated in a completely independent sample, and many questions remain to be answered. The CDC is already in the process of collecting more data on CFS from people in a different part of the US, as part of an even larger study

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First Published September 2006

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