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At least 19 recordsLinked to original sources
PubMed1978

Prenatal diagnosis of hemoglobin H disease.

Hemoglobin H disease was diagnosed prior to the twenty-second week of gestation in a pregnancy at risk for homozygous alpha-thalassemia using the technique of DNA-DNA hybridization. Fetal DNA was obtained from amniotic fluid fibroblasts obtained during the thirteenth week of gestation and grown in culture. The fetal fibroblast DNA was hybridized to radioactive alpha-globin cDNA. The number of alpha-globin genes present in the fetus was determined by comparing results of hybridization studies on the fetal DNA to similar studies on subjects with well-defined alpha-thalassemia syndromes and with normal subjects. The diagnosis of hemoglobin H disease was confirmed at birth by studies of the cord blood. This study confirms the ability of DNA-DNA hybridization techniques to distinguish the three-gene defect of hemoglobin H disease from the lethal four-gene defect of homozygous alpha-thalassemia.

Alpha-Globulins↗
PubMedDate not supplied

[Hemoglobin H: laboratory identification].

Hemoglobin H (Hb H) disease is an alpha thalassemia form characterized by low synthesis of alpha chain and high beta chain concentration; this unbalance induces the beta chain tetramers formation. Hb H is relatively frequent in Thailand and Greece. Isolated cases have been reported in Chinese, Filipinos, Malaysians. In the Near East occasional cases were observed in Greek Cypriots and Jordanian Arabs. Hb H carriers were found in Italy, Spain, Canada, Indonesia and other countries. In Brazil there are descendants of Italians, Chinese and people of negro origin who are carriers of Hb H. We identified the Hb H by electrophoresis, instability and characteristic inclusion bodies.

Adult↗
PubMed1978

Hemoglobin H disease in Sardinia: phenotypic and genetic observations.

In this study the clinical and hematological characteristics, the transmission pattern and the relative rates of globin chain synthesis were determined in the members of four Sardinian families with 14 patients affected by hemoglobin H disease. The severity of hemoglobin H disease in Sardinian subjects shows a high degree of variability. Clinically it usually appears intermediate between the hemoglobin H disease found in Oriental and Negro populations. The alpha/beta specific activity ratio was 0.42 +/- 0.10 indicating an analogous biochemical defect like that described in the Chinese. On the basis of hematological data and alpha/beta ratio, the genetics of hemoglobin H disease in Sardinians seem to follow a pattern similar to that observed in Orientals: one parent showing alpha-thalassemia-1 trait and the other alpha-thalassemia-2 trait. Parent offspring transmission of hemoglobin H disease did occur in 2 out of 6 hemoglobin H matings with spouses carrying the alpha-thalassemia-1 gene. This observation indicates either a high frequency of alpha-thalassemia trait in Sardinians or a high incidence of inbreeding. In one family the mating of a patient with hemoglobin H disease and a normal person produces 6/6 offspring with alpha-thalassemia-1. The genetic implications of this transmission pattern are discussed.

Adult↗
PubMed1992

[Acquired hemoglobin H disease in the early stage of erythroleukemia].

At the onset of erythroleukemia, the patient, a 74-year-old Swiss male, was also found to have microcytic-hypochromic anemia (Hb: 82 g/l, MCV: 69 fl, MCH: 21 pg). Further laboratory examinations revealed reduced hemoglobin stability, a hemoglobin H fraction of 3.0% on cellulose acetate-electrophoresis, and an abundance of hemoglobin H inclusion bodies in red cells. These findings, as well as the Swiss origin of the patient and his age at the onset of the disease, were consistent with acquired hemoglobin H disease. In addition to genetic hemoglobin H disease, acquired hemoglobin H disease was reported to be associated with myelodysplastic and myeloproliferative syndrome, or erythroleukemia and acute myelogenous leukemia. The literature contains fewer than 50 cases. It is suggested that the molecular basis of this rare disease involves a gene in trans to the alpha-globin genes reducing the expression of all four alpha-globin genes to approximately 10% of normal activity.

Aged↗
PubMed1978

Acquired hemoglobin H in refractor sideroblastic anemia. A preleukemic marker.

Two patients with idiopathic refractory sideroblastic anemia (IRSA) were found to have acquired hemoglobin H. Both developed leukemic syndromes. Six other patients with IRSA had normal hemoglobin electrpohoretic patterns, and none has developed acute leukemia in up to five years. We suggest that hemoglobin electrphoresis be performed routinely in IRSA. The finding of hemoglobin H in this population may be a relatively frequent occurrence and may serve to distinguish the preleukemic patients from those not destined to develop leukemia.

Aged↗
PubMed1979

Chemical cross-linking of hemoglobin H. A possible approach to introduce cooperativity and modification of its oxygen transport properties.

Native and reconstituted hemoglobin H molecules were cross-linked with glutaraldehyde at pH values close to the physiological. The Schiff base adducts were analysed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis before and after reduction with sodium borohydride. The major component had a molecular weight of about 31 000 which corresponded to the dimeric species of the beta subunit. In contrast to the native protein, which has very high oxygen affinity and no heme-heme interaction or 2,3-diphosphoglyceric acid effect, the modified hemoglobin H molecules showed cooperative oxygen binding, decreased oxygen affinity and a noticeable 2,3-diphosphoglyceric acid effect.

Biological Transport↗
PubMed1979

Molecular basis of hemoglobin-H disease in the Mediterranean population.

We investigated the molecular basis of hemoglobin-H disease by hybridization and restriction endonuclease mapping of the DNA in the Mediterranean populations. Of the 12 patients studied from Cyprus and Sardinia, 8 had the typical deletion defect with a single remaining alpha-globin gene. The nondeletion type of alpha-thalassemia was found in 3, and a "dysfunctional" gene in one. We conclude that the predominant cause of alpha-thalassemia in these populations is gene deletion.

Chromosome Deletion↗
PubMed1992

Intrathoracic extramedullary hematopoietic tumor in hemoglobin H disease.

We report a Chinese patient with hemoglobin H (Hb H) disease who developed intrathoracic extramedullary hematopoiesis (EMH) 17 years following splenectomy for a blunt abdominal injury. The patient initially presented with extreme hyperbilirubinemia and multiple intrathoracic tumors. Hb H disease was diagnosed after investigation, and the marked jaundice, which declined gradually after supportive treatment, was attributed to his chronic hemolysis superimposed on an acute hepatitis C virus infection. A biopsy of the intrathoracic tumors revealed an EMH. Intrathoracic EMH, which is usually encountered in patients with beta-thalassemia and hereditary spherocytosis, has never been reported in Hb H disease. In areas where thalassemia is prevalent, EMH should be considered in the differential diagnosis of patients who have chronic anemia with asymptomatic intrathoracic tumor to avoid unnecessary surgical interventions.

Adult↗
PubMed1979

Modification of hemoglobin H disease by sickle trait.

The rarity of hemoglobin (Hb) H disease in combination with sickle trait may be due in part to the absence of actual Hb H in individuals who, nonetheless, have inherited the deletion of three alpha-globin genes. We describe here a boy with persistent microcytic, hypochromic anemia despite adequate iron stores, who exhibited splenomegaly with a normal reticulocyte count and only rare inclusions in circulating erythrocytes. Starch gel electrophoresis and isoelectric focusing at age 5 yr showed 21% Hb S, persistent Hb Bart's, but no Hb H. Recticulocyte alpha/non-alpha globin chain synthesis ratio was 0.58 at age 5. The mother (Asian) had laboratory evidence of alpha-thalassemia trait and the father (Black) had sickle trait. The nature of alpha-thalassemia in this patient was investigated both by liquid hybridization and by the Southern method of gene mapping, in which DNA is digested with restriction endonucleases and the DNA fragments that contained the alpha-globin structural gene identified by hybridization with complementary DNA. The patient had only one alpha-globin structural gene, located in a DNA fragment shorter than that found in normal or alpha-thalassemia trait individuals, but similar to that present in other patients with Hb H disease. Morphologic studies of bone marrow by light and electron microscopy revealed erythroid hyperplasia with inclusions in polychromatic and orthochromatic erythroblasts, suggesting early precipitation of an unstable hemoglobin. The lack of demonstrable Hb H may be the result of both diminished amounts of beta(A) available for Hb H formation (since one beta-globin gene is beta(S)) and the greater affinity of alpha-chains for beta(A) than beta(S)-globin chains leading to the formation of relatively more Hb A than Hb S. The presence of a beta(S) gene may thus modify the usual clinical expression of Hb H disease.

Anemia, Sickle Cell↗
PubMed1992

Hemoglobin H disease in children.

One hundred and ten children with hemoglobin H (Hb H) disease who attended the hematology unit of the Department of Pediatrics at Songklanagarind Hospital from 1982 to 1988 were studied. Hb Constant spring (Hb CS) was found in 55 patients. Four patients, two with Hb CS, were diagnosed during the newborn period. Anemia and jaundice were the main symptoms in three neonates, while the fourth one was found to have anemia with hepatosplenomegaly. Nine infants were diagnosed in the first year of life with the chief symptoms of anemia with or without fever. Two of them needed blood transfusions. Hb H was found in only three infants, while Hb Bart's was the constant finding in every infant. The Hb H children with Hb CS had a more severe clinical course than the group without Hb CS. The levels of Hb at steady state were found to be lower and the reticulocyte counts, red cells with inclusion bodies and Hb H were higher in patients with Hb CS. The clinical picture of acute hemolysis in Hb H children can be found in the neonatal period and the difference in clinical severity between the two genotypes of Hb H disease seems to develop from the first year of life.

Age Factors↗
PubMed1979

A molecular basis for hemoglobin-H disease in American blacks.

We have applied gene counting and restriction endonuclease mapping techniques to the study of two American black families in which there were one or more cases of HbH disease. We found deletions of three of the four normal alpha-globin genes in individuals with HbH disease. In two of these individuals, the chromosome containing the single alpha gene could have originated by crossing over between mispaired alpha genes, resulting in a deletion of about 4.2 kilobases (kb).

Black People↗
PubMed1979

Acquired hemoglobin H disease in idiopathic myelofibrosis.

A 68-year-old male, diagnosed 1 year previously as having myelofibrosis, developed hemolysis, red cell inclusions, and 37% Hb H. The alpha/beta globin synthetic ratio for circulating reticulocytes, determined by 3H-leucine incorporation and globin chain separation by carboxymethylcellulose chromatography in urea, was 0.049. When total RNA was purified from peripheral blood cells and translated in a wheat germ cell-free translation system, the alpha/beta ratio of the translation products was 0.26, indicating mRNA as a major cause of the globin synthetic imbalance. This study demonstrates that myelofibrosis is one setting in which acquired Hb H disease occurs; that the synthetic imbalance may be extreme; and that it can be associated with an imbalance in the activities of specific globin mRNAs.

Aged↗
PubMed1992

Screening for alpha-thalassemia. Correlation of hemoglobin H inclusion bodies with DNA-determined genotype.

We evaluated potential screening protocols for alpha-thalassemia in a group of 80 patients whose genotypes were determined by Southern blot analysis with alpha- and zeta-globin DNA probes. Erythrocyte inclusion bodies were measured by a modified brilliant cresyl blue test. Erythrocyte indices and iron status were also measured. The brilliant cresyl blue test reliably detects couples at risk for hemoglobin Bart's hydrops fetalis. Measurement of the number of inclusion bodies differentiates the alpha-thalassemia genotypes in the absence of a coincident beta-chain synthesis deficiency, such as hemoglobin E or beta-thalassemia. The test appears to identify patients, such as those with the Thai and Filipino deletion variants, whose alpha-thalassemia cannot be definitively characterized by DNA testing when only alpha- and zeta-globin probes are used in the analysis. We also found evidence of elevated serum ferritin levels in many patients with deletion of two or three alpha-globin genes. This study shows that most routine screening for alpha-thalassemia can be performed with three simple tests: (1) the brilliant cresyl blue inclusion study, (2) erythrocyte indices, and (3) iron studies. Analysis with DNA probes is needed in only some circumstances.

Blotting, Southern↗
PubMed1992

Size distribution curves of blood cells in thalassemias and hemoglobin H diseases.

Thalassemias and hemoglobinopathies in Thailand have been examined with a blood cell counter based on electroimpedance principle and obtained size distribution curves of red cells and platelets. Among various disorders, beta-thalassemia/hemoglobin E and homozygous hemoglobin Constant Spring showed severe anemia. Their red cell size distribution curve shifted to the left and overlapped with the platelet size distribution curve. Red cell distribution width expressed by coefficient of variation and the degree of the overlapping were stronger in beta-thalassemia/HbE than HbH. Heterozygous beta-thalassemia showed a narrow red cell distribution curve width with small standard deviation and low England's value. Although the overlapping of size distribution curves cause inaccurate red cell count and platelet count, careful observation of the size distribution curves was proved to have high diagnostic value.

Blood Platelets↗