Chronic fatigue syndrome may have genetic link

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Chronic fatigue syndrome may have genetic link

Largest study on illness finds unique gene patterns governing brain activity

April 20, 2006

ATLANTA - Chronic fatigue syndrome appears to result from something in

people’s genetic makeup that reduces their ability to deal with physical and

psychological stress, researchers reported Thursday.

The research is being called some of the first credible scientific evidence

that genetics, when combined with stress, can bring on chronic fatigue

syndrome — a condition so hard to diagnose and so poorly understood that

some question whether it is even a real ailment.

Researchers said the findings could help lead to betters means of diagnosing

and treating chronic fatigue syndrome and predicting those who are likely to

develop the disorder, which is characterized by extreme, persistent

exhaustion.

“The results are ground-breaking,” said Dr. Reeves of the Centers

for Disease Control and Prevention.

Reeves said the study demonstrates that people with chronic fatigue syndrome

are unable to deal with everyday challenges and adversity. That could

include injuries, illnesses, divorce, even stressful jobs, the researchers

said.

1 million Americans suffer from condition

The CDC estimates more than 1 million Americans have the condition, with

women suffering at four times the rate among men.

The research is contained in a collection of 14 articles published in this

month’s issue of Pharmacogenomics, a scientific journal.

The centerpiece is a study of 227 people with chronic fatigue syndrome in

Wichita, Kan. Over two days, doctors performed psychiatric evaluations,

assessed their physical limitations, looked at their medications, and tested

their blood and urine for chemical and biological abnormalities.

The data included 500 clinical measures and 20,000 measures of gene

expression, which is the process by which genes regulate cell activity.

The information was then given to four teams of investigators, including

medical experts, molecular biologists, mathematicians and engineers.

Among their findings: Chronic fatigue patients tested with high levels of

allostatic load, which is a stress measure of hormone secretions, blood

pressure and other signs of wear and tear on the body. The patients were

about twice as likely to have a high allostatic load index as people who did

not have chronic fatigue syndrome.

Link to stress management

The researchers also found that certain genetic sequence variations in five

stress-moderating genes showed up consistently in chronic fatigue patients.

And they identified at least five subtypes of chronic fatigue syndrome,

classified according to criteria that include their genetics and the way

their symptoms unfold.

“Because we have this information, we’re going to be able to predict who is

more susceptible to certain types of stressful events,” said Suzanne Vernon,

molecular biology team leader for the CDC’s CFS Research Laboratory in

Atlanta.

Chronic fatigue syndrome is a complex illness characterized by at least six

months of severe fatigue that is not helped by bed rest. Patients also

report such symptoms as muscle pain and impaired memory.

The cause has never been identified, and there are no specific tests for it.

It was first identified in the 1980s, but many people — including some

health professionals — have greeted CFS patients with skepticism, regarding

it as the complaint of “a bunch of hysterical upper-class white women,” said

Reeves, who heads the CDC’s CFS research program.

The CDC research joins a cluster of studies published in the past eight

months that implicate certain genes and gene expressions as a contributing

factor to the condition, said Kim McCleary, president of the Charlotte,

N.C.-based Chronic Fatigue and Immune Dysfunction Syndrome Association of

America.

The findings contribute to an evolving, complicated explanation of how

genes, stress and other factors work together to cause and perpetuate the

illness, she said.

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