Fetal hemoglobin (HbF) levels vary considerably in healthy normal adults. The distribution of HbF and F cells, erythrocytes that contain measurable HbF, in healthy adults is continuous, although most adults have HbF of less than 0.6% of total Hb. Approximately 10 to 15% of individuals have increases of HbF ranging from 0.8% to 5%, a trait often referred to as hereditary persistence of fetal hemoglobin (HPFH), usually distributed unevenly among red cells. When coinherited with beta-thalassemia (see 613985) or sickle cell anemia (603903), HPFH can increase HbF output to levels that are clinically beneficial (Thein et al., 2007).
For a general phenotypic description and a discussion of loci that may affect fetal hemoglobin levels, see HBFQTL1 (141749). [from OMIM]
Biochemical Genetics Tests
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