Hereditary Persistence of Fetal Hemoglobin: A Study of 79 Affected Persons in 15 Negro Families in Baltimore

Hereditary persistence of fetal hemoglobin is an anomaly of hemoglobin production apparently caused by a mutant gene that inhibits synthesis of hemoglobins A and A2. Alkali-resistant hemoglobin indistinguishable from hemoglobin F of umbilical cord blood is produced, presumably as a compensatory phenomenon, so that neither anemia nor hypochromia of the red cells occurs. The data summarized are compatible with the hypothesis that function of the loci of the β and δ chains of globin is wholly suppressed, quite possibly by a mutant "operator" gene affecting linked structural loci. Heterozygotes for the anomaly have high concentrations of hemoglobin F in the erythrocytes, with a remarkably uniform distribution of fetal hemoglobin throughout the red cell population. Erythrocytes of persons with the anomaly resemble adult red cells with respect to the non-hemoglobin proteins and the oxygen dissociation curve. Experience with 79 affected Negroes in Baltimore is compared with that reported by other investigators. The occasional difficulty in differentiating the anomaly from other conditions, particularly thalassemia, is emphasized.