Chronic fatigue among Gulf War veterans seems to be associated with a particular variant of the DCP1 gene, according to new research.

The gene encodes angiotensin-converting enzyme (ACE), and comes in two types - I or D. Since everyone has two copies of the gene, the possible combinations (or genotypes) are II, DD or ID.

Drs. Georgirene D. Vladutiu and Benjamin H. Natelson explain in the journal Muscle and Nerve that the D type of the gene is associated with increased risk for heart disease, whereas the I variant is associated with enhanced endurance and physical performance.

Dr. Vladutiu, at the State University of New York at Buffalo, and Dr. Natelson, at the VA Medical Center in East Orange, New Jersey, evaluated the genotypes of 49 Gulf War veterans with chronic fatigue syndrome, 30 healthy Gulf War veterans and 45 comparison “control” subjects.

Only 15 percent of the veterans with chronic fatigue had at least one copy of the I type of the DCP1 gene, compared with 48 percent of health veterans. When it came to two copies of the I variant (the II genotype), the numbers were 8 percent versus 35 percent.

Veterans with the DD genotype were eight times more likely to develop chronic fatigue than were those with the II genotype.

The researchers did not observe a similar pattern when they tested 61 non-veterans with chronic fatigue syndrome and 45 non-veterans without the syndrome.

Overall, the findings indicate that “an interaction between these genetic (variants) and some factor unique to deployment to the Persian Gulf,” such as exposure to battlefield stress, the researchers suggest.

SOURCE: Muscle and Nerve, July 2004.