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At least 19 recordsLinked to original sources

Hemoglobin Freiburg: abnormal hemoglobin due to deletion of a single amino acid residue.

Structural characterization of a new variant of human hemoglobin (adult), designated hemoglobin Freiburg, indicates the deletion of the valyl residue No. 23 from an otherwise normal beta-chain. The formula may be written (alpha2)beta(2)(23val-0). The abnormal hemoglobin is present with hemoglobin A in the proposita and in two of her three living children, but is not detectable in her parents. We postulate that this variant represents a triplet base deletion which most likely resulted from an unequal crossing-over between two normal betachain loci during meiosis in one of the parents of the proposita.

Adult↗

[Abnormal hemoglobins in Algeria].

The existence of frequent hemoglobin abnormalities raises a Public Health problem in Algeria. The presence of genes for hemoglobin S, hemoglobin C and thalassemia in various regions of the country causes severe congenital hemolytic anemias: thalassemia, sickle-cell anemia, S thalassemia, association of HbS and HbC. These diseases are often invaliding requiring frequent admissions to hospital and have a high social cost. We have also observed certain rare hemoglobins, of which some, hemoglobin Setif, hemoglobin D Ouled Rabah were described for the first time in Algerians. They are not pathogenic in the heterozygous state.

Algeria↗

An unusual case of leukemia with high fetal hemoglobin: demonstration of abnormal hemoglobin synthesis localized in a red cell clone.

A high level of fetal hemoglobin was found in an 8-yr-old boy without any hematologic disorders except for a moderate anemia. The absence of hemoglobin abnormalities in the parents led us to suspect a latent malignant disease that, on follow-up, was confirmed to be myelomonocytic leukemia. Hemoglobin biosynthetic studies provided evidence of unbalanced synthesis of globin subunits by reticulocytes, while the production of non-alpha chains was equal to that of alpha chains in bone marrow cells. The expression of red cell antigen i was increased, while those of I, A, and A1 antigens were found to decrease progressively. Two populations of erythrocytes, A-positive and A-negative, were distinguished and could be separated by differential agglutination. Unbalanced globin chain synthesis, increased fetal hemoglobin, and antigenic changes of the membrane were shown to be restricted to the A-negative population. The biologic data were not entirely consistent with a genuine reversion to fetal erythropoiesis. The question remains of a polychromosomal lesion of either quiescent F cells or adult stem cells.

ABO Blood-Group System↗

Screening for abnormal hemoglobins: who, when, and how.

Sickle cell and abnormal hemoglobin screening programs should not be undertaken lightly but rather should have a specific purpose or purposes. If the aim is to detect only sickle hemoglobin, a certain strategy is necessary. If the goal is to detect all abnormal hemoglobins and genetic counseling is planned, another approach should be used. A simple solubility test detects sickle hemoglobin with high reliability, but deals with no other abnormal hemoglobins. Hemoglobin electrophoresis, followed by other tests as indicated, is then necessary to ascertain other abnormal hemoglobins in addition to hemoglobin S.

Anemia, Sickle Cell↗

Thalassemia and abnormal hemoglobin.

Thalassemia and abnormal hemoglobins are common genetic disorders in Asia. Thalassemia is not only an important public health problem but also a socio-economic problem of many countries in the region. The approach to deal with the thalassemic problem is to prevent and control birth of new cases. This requires an accurate identification of the couple at high risk for thalassemia. However, the diagnosis of thalassemia carrier states need several tests which are not practical for screening the population at large. Recently we have used two simple laboratory tests to screen for potential thalassemia carriers and hemoglobin E individuals. There is also a new development in using the automatic HPLC to diagnose thalassemic diseases and the carriers. This system gives both qualitative and quantitative analysis of hemoglobin components in the same run with good precision and reproducibility. The system has been applied to study thalassemia and abnormal Hb in adult and cord blood. This system has enabled us to do both prenatal and postnatal diagnosis of thalassemia within the few minutes. However, none of these screening tests can accurately give specific diagnosis of the thalassemia genotype. Specific thalassemia mutation can be carried out by DNA analysis. Many DNA techniques have been used for point mutation detection and small deletion. For the last few years there is a development of DNA chip technology that has been applied for thalassemia mutation as well. Clinically, thalassemia is very heterogeneous in the manifestation. In spite of seemingly identical genotypes, severity of beta thalassemic patients can vary greatly. Heterogeneity in the clinical manifestation of beta thalassemic diseases may occur from the nature of beta globin gene mutation, alpha thalassemia gene interaction and difference in the amount of Hb F production which is partly associated with a specific beta globin haplotype. However, there is still some beta thalassemia cases that have a mild clinical symptom without those known genetic fators interaction suggesting that there are other additional factors responsible for the mildness of the disease.

Asia↗

[Differentiation of selected abnormal hemoglobin by PCR-RFLP method].

Abnormal hemoglobin is one of the most frequent genetic disorder, of which about 700 variants have been reported in the world. Some abnormal hemoglobins such as HbS and HbC are endemic among limited human populations. We have found five subjects with abnormal hemoglobin in routine hematology analysis using an automated system Sysmex NE-7000. We isolated genomic DNA from the peripheral blood leukocyte of each subject, and amplified a 558 bp fragment of DNA including the entire exons 1 and 2 as well as intron 1 of the beta-globin gene. The amplified DNA fragments were subjected to direct sequencing by the dideoxy termination method on an automated DNA sequencer. The sequence analysis showed the abnormalities including HbA/C, HbS/C, HbE/E, and HbA/G-Szuhu. In the present study, we report a simple method for the mutual differentiation of these abnormal hemoglobins using restriction fragment length polymorphism (PCR-RFLP) method. Digestion of the amplified fragments described above with a restriction enzyme MnlI gave different RFLP patterns for HbA, HbC or S, HbE, and for HbG-Szuhu. RFLP using another enzyme, DdeI, could distinguish for HbS from HbC.

Hemoglobins, Abnormal↗

[Prevalence of hemoglobin abnormalities in Kebili (Tunisian South)].

BACKGROUND: Hemoglobin abnormalities constitute a public health problem in many countries in the world. In Tunisia, these disorders were thought to affect only the North-western population. However, the existence of hemoglobinosis concentration in Kebily in south Tunisia has been suggested by previous work. In order to estimate their frequencies, we performed a screening of hemoglobin abnormalities in the North-Kebili region, to establish a prevention program of the homozygous forms. METHODS: This screening concerned all 1st and 2nd grade primary school pupils in North Kebily. After a questionnaire, a blood sample was drawn from every child. Hemogram, sickling test, and hemoglobin electrophoresis at alkaline pH were performed for all children. Hemoglobin electrophoresis at acid pH and a specific hemoglobin A2 titration were performed for some children. RESULTS: The study concerned 1,400 children, aged between 5 and 12 years, the mean age was 7 years and 7 months +/- 10 months. Consanguinity rate and coefficient were respectively 44% and 2249 x 10(5). Endogamy was very high. The global rate of hemoglobin abnormalities was 9.4%. Drepanocytosis with a rate of 4.9% was the most frequent, followed by beta thalassemia (3.1%) and C hemoglobinosis (1.6%). These abnormalities were unequally distributed; very frequent in some localities, they were quite absent in others. CONCLUSIONS: This study revealed a hemoglobinosis concentration in Tunisia, which can be classified second after that of Beja in North-western Tunisia. The heterogeneous distribution of the hemoglobin abnormalities in North-Kebili region and the high consanguinity and endogamy rates constitute factors that promote homozygous and double heterozygous forms to arise and justify the elaboration of a preventive strategy.

Age Factors↗