Hereditary persistence of fetal hemoglobin: a study of 79 affected persons in 15 Negro families in Baltimore.

H EREDITARY PERSISTENCE OF FETAL HEMOGLOBIN is a term tentatively applied to a specific inherited anomaly manifested throughout life by the presence of large amounts of fetal hemoglobin in the erythro-cytes in the absence of anemia or clinical manifestations. The abnormality is attributable to a single autosomal genetic factor. Since the primary effect of the mutant gene is unknown, designations which identify the anomaly with thalas-semia, or terms such as " the F gene, " are undesirable. Persons heterozygous for the condition but otherwise normal have, on the average, 26 per cent fetal hemoglobin in their red cell hemolysates. This congenital abnormality must be differentiated from other disorders in which fetal hemoglobin may persist in adult life, in particular thalassemia, which at times it closely resembles. Occurrence First discovered in Nigeria by Edington and Lehmann,1'2 hereditary persistence of fetal hemoglobin has been encountered in Negroes in Uganda,3 Jamaica4'5 and in the United States,#{176}} 2 and in a single Caucasian family in Greece.3 The only extensive survey to determine the frequency of the abnormality was performed in Baltimore, where five affected persons were found among 5000 Negroes examined.9'' In a similar study in Philadelphia, one affected person was discovered in a survey of 1000 Negroes.8 Characte'rkk 'tics of the Anomaly The anomaly has been encountered in the homozyous and heterozygous state. Heterozygotes have displayed no other abnormality of hemoglobin synthesis (A-F) or have been heterozygous in addition for hemoglobin S (S-F), hemoglobin C (C-F) or thalassemia (Thai-F). Homozggote: Only one person apparently homozygous for the anomaly has been discovered,'1 a child of 33 months at the time of the present study. When first seen at the age of 15 months, he had hypochromic anemia which responded promptly and completely to the oral administration of ferrous