Contribution to the study of molecular defects of hemoglobin in the Brazilian population

The hemoglobinopathies belong to a diverse group of inherited disorders characterized by the reduced synthesis of one or more globin chains (thalassemia) or the synthesisof a structurally abnormal hemoglobin (Hb). Approximately 900 different hemoglobin variants characterized by mutations involving alpha, beta, gamma, and delta globin chains have been described worldwide. In Brazil, the high degree of ethnic admixture among native Americans and African and European descendants has produced elevated frequencies of Hb alterations. The aim of the present study was to characterize globin chain mutants based on classical laboratory tests and molecular analyses to supply detailed informationabout the Hb diseases to health professionals and to contribute to the knowledge of abnormal hemoglobins in Brazil. A total of 242 samples were submitted to classical tests selected for hemoglobinopathies, and molecular screening was carried out by PCR-based techniques that included allele-specific PCR, multiplex PCR, restriction enzyme analysis PCR, and direct sequencing. After conducting the classical tests, the samples were divided into five groups in accordance with the mutant chain. The groups with alpha and beta globin chain mutants were the most frequent, with 81 samples each. Another group with a large number of samples was that of unidentified mutants, with 56 samples. The delta and fusing delta/beta globin chain groups had fewer numbers of samples, respectively, 13 and 11. The most frequent electrophoretic profile was the Hb S-like, followed by fast variants. Some sample of the beta globin chain group could only be identified after sequencing, such as the samples Hb D-Los Angeles, Hb Korle-Bu, Hb K-Woolwich, Hb E, Hb Deer Lodge, Hb Osu-Christiansborg, and Hb Ohio. It was possible to detect a previously undescribed variant in four individuals of this sampling, who were not related and from different locations. For the alpha globin chain mutants, sequencing of the...

Description of electrophoretic and chromatographic hemoglobin profile of Rhinoclemmys punctularia

Studies of the hemoglobin pattern in Brazilian reptiles are important for determining ecological and phylogenetic relationships, but they are scarce. Peripheral blood samples were obtained from 7 males and 18 females of Rhinoclemmys punctularia. The hematological profile was based on the total hemoglobin and hematocrit values. The hemoglobin profile was obtained using electrophoretic procedures at different pH, isoelectric focusing, globin chain electrophoresis, and HPLC. The hematocrit (31 +/- 2%) and total hemoglobin (7.5 +/- 0.2 g/dL) values did not indicate gender variations. Alkaline pH electrophoresis of the total blood samples treated with 1% saponin demonstrated the presence of four well-defined hemoglobin fractions, one major component (fraction I), showing cathodic migration and three others faster than fraction I with anodic migration. When the samples were precipitated with chloroform, only two hemoglobin fractions were observed, similar to fractions I and III from the first procedure. Isoelectric focusing and HPLC showed the same pattern. With acid and neutral pH electrophoresis, two fractions with anodic migration were observed. The globin chain identification at alkaline pH showed two fractions, but four fractions were observed at acidic pH, suggesting that different polypeptide chains are involved in the hemoglobin molecule. The chromatographic separation of the total blood sample demonstrated that the major fraction comprised 81.9% and the minor 18.1%. The results obtained demonstrated a similarity between these hemoglobin components and those of some Chelidae reported in the literature for both land and aquatic animals, reflecting the adaptation to environmental conditions.

HPLC determination of hemoglobins to establish reference values with the aid of statistics and informatics

The purpose of the present study was to establish reference values for hemoglobins (Hb) using HPLC, in samples containing normal Hb (AA), sickle cell trait without alpha-thalassemia (AS), sickle cell trait with alpha-thalassemia (ASH), sickle cell anemia (SS), and Hb SC disease (SC). The blood samples were analyzed by electrophoresis, HPLC and molecular procedures. The Hb A2 mean was 4.30 +/- 0.44% in AS, 4.18 +/- 0.42% in ASH, 3.90 +/- 1.14% in SS, and 4.39 +/- 0.35% in SC. They were similar, but above the normal range. Between the AS and ASH groups, only the amount of Hb S was higher in the AS group. The Hb S mean in the AS group was 38.54 +/- 3.01% and in the ASH it was 36.54 +/- 3.76%. In the qualitative analysis, using FastMap, distinct groups were seen: AA and SS located at opposite extremes, AS and ASH with overlapping values and intermediate distribution, SC between heterozygotes and the SS group. Hb S was confirmed by allele-specific polymerase chain reaction. The Hb values established will be available for use as a reference for the Brazilian population, drawing attention to the increased levels of Hb A2, which should be considered with caution to prevent incorrect diagnoses.

Hemoglobin I-Philadelphia [alpha 16 (A14) LYS-->GLU] heterozygote among blood donors from Brazil

We describe a heterozygous case of Hb I-Philadelphia [alpha 16 (A14) LYS-->GLU] in a blood donor from the Acre State Blood Bank, in the Brazilian Amazon region. We confirmed the mutation by electrophoretic and chromatographic methods and by DNA sequencing. A literature search showed that this is the first description of this alpha globin mutant in a Brazilian Caucasian group. We also emphasize the importance of the hemoglobin study in blood donors for the purpose of the genetic counseling and quality assurance of the blood to be transfused. Screening tests for hemoglobin mutants are also important for gathering anthropological information about the Brazilian population.