An Adult Homozygous for Persistent Fetal Hemoglobin

Target cells were predominant in the blood smear of a 53-year-old negro man admitted for a perforated duodenal ulcer. Hemoglobin was 100% fetal by alkali denaturation, cellulose acetate and starch gel electrophoresis, and cation and anion exchange chromatography. Restudy more than 2½ years later when the patient was asymptomatic revealed mild microcytosis, anisocytosis, poikilocytosis, numerous target cells, and erythrocytosis. Abnormalities consistent with the heterozygous state for persistent fetal hemoglobin were demonstrated in both parental lines. This is the first recognized instance of homozygosity for persistent fetal hemoglobin in an adult.