Sickle-Cell Alert

About one out of twelve black Americans carries a single gene for sickle-cell anemia. That trait, doctors have long believed, is basically benign, since the blood disorder strikes only when two defective genes are present. But a report in last week's New England Journal of Medicine challenges this assumption. In a study of more than 2 million military recruits, doctors at Washington's Armed Forces Institute of Pathology found that sickle-cell carriers run 40 times the normal risk of sudden death when they undergo the rigors of basic training. The danger appears to increase with age.

According to Dr. John Kark, who directed the study, "We don't know what process leads to sudden death," but he speculates that sickle-cell carriers may be unusually vulnerable to dehydration during prolonged exertion. Kark does not believe affected blacks need worry about participating in strenuous sports. They are less stressful than boot camp, he says, and probably pose little risk. He does recommend the Army begin routine screening for the trait: "It would only be fair to recruits."