Ratio of sickle-cell anemia hemoglobin to normal hemoglobin in sicklemics.

The erythrocytes of certain human individuals undergo a reversible change in shape known as sickling if deprived of oxygen (1, 2). Taliaferro and Huck (3) postulated that this characteristic is transmitted by a single dominant gene, but failed to account genetically for the wide divergence in clinical signs and symptoms among individuals who possess sickling red cells. A small fraction, about 1 in 40, of these individuals have a severe chronic anemia called sickle-cell anemia; the others have no symptoms which can be associated with this erythrocyte characteristic, and their condition is termed sickle-cell trait or sicklemia (4). Neel (5) has postulated that there exists in the Negro population a gene which in the heterozygous condition results in sicklemia and in the homozygous condition in sickle-cell anemia. His statement is based on the finding that the trait was present in every parent of a sickle-cell anemia patient that he tested. This hypothesis is in accord with the results of recent electrophoretic studies of the hemoglobins in these conditions (6, 7). These studies showed that the erythrocytes of individuals with sickle-cell anemia contain a new kind of hemoglobin, different from that of normal individuals, and also that the hemoglobin of sicklemic persons consists of two components which behave electrophoretically as normal hemoglobin and sickle-cell anemia hemoglobin. These results have aided in the clarification of both the genetic and the clinical aspects of sickle-cell anemia and sickle-cell trait. In the attempt to obtain information about the nature of sickle-cell anemia hemoglobin, amino acid analyses of hydrolysates of normal, human, adult hemoglobin and of sickle-cell anemia hemoglobin were carried out, which showed that there are probably small differences