The symptoms of chronic fatigue syndrome are related to abnormal ion channel function

The pathogenesis of chronic fatigue syndrome (CFS) is unknown but one of th e most characteristic features of the illness is fluctuation in symptoms wh ich can be induced by physical and/or mental stress. Other conditions in wh ich fluctuating fatigue occurs are caused by abnormal ion channels in the c ell membrane. These include genetically determined channelopathies, e.g. hy pokalemic periodic paralysis, episodic ataxia type 2 and acquired condition s such as neuromyotonia, myasthenic syndromes, multiple sclerosis and infla mmatory demyelinating polyneuropathies. Our hypothesis is that abnormal ion channel function underlies the symptoms of CFS and this is supported also by the finding of abnormal cardiac-thallium(201) SPECT scans in CFS, simila r to that found in syndrome X, another disorder of ion channels. CFS and sy ndrome X can have identical clinical symptoms. CFS may begin after exposure to specific toxins which are known to produce abnormal sodium ion channels . Finally, in CFS, increased resting energy expenditure (REE) occurs, a sta te influenced by transmembrane ion transport. The hypothesis that ion chann els are abnormal in CFS may help to explain the fluctuating fatigue and oth er symptoms. (C) 2000 Harcourt Publishers Ltd.