[Blood].

By W. N. POWELL, M.D., J. G. RODARTE, M.D., AND J. V. NEEL, PH.D., M.D. A LTHOUGH in recent years the blood disorders sickle cell disease and thalassemia have both been studied extensively from the genetic standpoint, thus far the simultaneous occurrence within a single family group of the genes responsible for these two diseases has not been reported in the medical literature of the United States. The significance of the discovery and study of such families in elucidating the relationship between these genetically similar blood dyscrasias is obvious. Since 1944 we have had under observation three generations of a family of Sicilian ancestry displaying both the sickle cell trait and thalassemia minor. * The finding in Mike D., the first member of the family studied, of a severe hemolytic