Study Defines Chronic Fatigue Syndrome's Biological Underpinnings

Chronic fatigue syndrome appears to have its roots in genetics, yet also includes additional elements -- environmental factors, risk-conferring behaviors and patients’ responses to stressors -- according to research released April 20 by the CDC and published in the April issue of Pharmacogenomics.

The research indicates people who have chronic fatigue syndrome, or CFS, have a genetic makeup that impairs their ability to cope physiologically with life stresses, such as infection, injury or other adverse events, said William Reeves, M.D., chief of the CFS public health research program at the CDC.

The National Library of Medicine defines CFS as a condition "of prolonged and severe tiredness or weariness … that is not relieved by rest and is not directly caused by other conditions." To be diagnosed with CFS, the definition adds, "The tiredness must be severe enough to decrease ability to participate in ordinary activities by 50 percent." Other CFS symptoms include sore throat, painful lymph nodes in the neck or armpits, pain that moves from joint to joint but is not accompanied by redness or swelling, mild fever, trouble with short-term memory or concentration, and difficulty sleeping.

Using a team of experts in medicine, molecular biology, epidemiology, genomics and related sciences, the CDC study interpreted information gathered from 227 patients with CFS or other unexplained fatiguing illness and nonfatigued controls.

"There is a clear biologic basis for CFS," said Suzanne Vernon, Ph.D., leader of the CDC's molecular epidemiology team for the CFS Research Laboratory, in an April 20 CDC announcement about the research findings.

CFS affects more than 1 million Americans, mostly women between the ages of 40 and 60.