THE INCIDENCE AND SIGNIFICANCE OF THE SICKLE CELL TRAIT

Abstract

IF ONE takes a drop of blood from each member of an unselected series of negroes, seals the drops under cover-slips, and examines them micro-scopically over a period of hours, he observes striking curved and pointed distortions of the erythrocytes in an appreciable number of the preparations. (Figure 1.) Erythrocytes assuming such bizarre stellate shapes are called " sickled cells " and individuals whose erythrocytes are capable of under-going such a metamorphosis under suitable conditions are said to possess the " sickle cell trait. " The anomaly is hereditary and is thought to be trans-mitted as a dominant Mendelian characteristic. Within the large group of those who inherit the sickle cell trait, an undetermined number, due to factors unknown, develop varying degrees of " sickle cell anemia, " a hemolytic type of blood dyscrasia with characteristic clinical and pathological features. Estimations of the frequency of occurrence of the sickle cell trait have been recorded by a number of observers, but the number of individuals examined has been relatively few; most of the studies have been made on