Sickle-cell anemia

Sickle-cell anemia, one of many hereditary blood diseases caused by chemically abnormal hemoglobin in the red blood cells, occurring almost exclusively among blacks. Rather than the normal disk shape, the red cells have distorted (crescent) shapes when their oxygen supply is low. It is from this unusual appearance of the red blood corpuscles that the disease and its abnormal hemoglobin derive their names, the hemoglobin being known as the sickle hemoglobin, or hemoglobin S. The disease was first described by J. B. Herrick in 1910, but it was not until 1949 that Linus Pauling and his associates demonstrated the basic defect to be in the hemoglobin molecule of the red blood cells. Since the discovery of the sickle hemoglobin, more than 100 other abnormal hemoglobins have been described. Characteristics of the disease, for which there is no cure, include fever, anemia, and pain in the joints and abdomen.