Hereditary hemoglobin disorders in a Brazilian population.

A survey of hereditary hemoglobin disorders in a mixed Brazilian population of the northeast of the State of S. Paulo revealed a 5.3% incidence of abnormal phenotypes among 400 schoolchildren, 4.5% among 602 mothers and 2.8% among 606 newborns. The most common findings were AS (1.9%), AC (0.8%) and beta-thalassemia (0.8%) heterozygotes, which amount to 3.5% of the sample. In a second selected population of 1,023 patients of the Hematologic Clinic of the University Hospital and their relatives, 471 cases of hemoglobinopathies were detected. The most frequent anomalies were heterozygous beta-thalassemia (35.2%) and Hb S (32.5%), followed by sickle-cell anemia (13.0%), homozygous beta-thalassemia (4.0%) and sickle-cell/beta-thalassemia (4.0%). Other defects detected were delta-beta-thalassemia, Hb C, Hb Hasharon and Hb A2'. One family with alpha-thalassemia has been identified that included a girl with Hb H disease. The significance of these findings is discussed with regard to the racial origin of the population of this region.