The diseases sickle cell anemia and Cooley's anemia (also known as thalassemia or Mediterranean anemia) have associated with them "minor" or "trait" forms of the disease in which the symptomatology is minimal, and the abnormalities in the red cells are correspondingly less. Extensive genetic studies carried out on these diseases [1-4] have led to the conclusion that in each case the trait is inherited as a Mendalian dominant, the person being heterozygous in the sickle cell gene or Cooley's gene. Homozygosity in either of these genes leads to the corresponding anemia.
Our understanding of sickle cell anemia has improved considerably with the discovery of an abnormal hemoglobin and a molecular interpretation of the pathological behavior of the red cell. [5] In that disease it was possible to demonstrate heterozygosity and homozygosity directly, by observing varying amounts of the abnormal hemoglobin.
Liquori [6] has recently reported the pr'esence of fetal hemoglobin in cases of Cooley's anemia. We have carried out a number of experiments which support his findings, and have extended the investigation to include cases of Cooley's trait, for which no fetal hemoglobin was found. A hypothesis is advanced to explain these facts
