Alpha Thalassaemia in Adults with Sickle‐Cell Trait

Steinberg, Martin H.; Adams, Joel C.; Dreiling, Bernard J.

doi:10.1111/j.1365-2141.1975.tb00514.x

Cited by 62 publications

(26 citation statements)

References 23 publications

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“…We determined the α-globin gene status of our AS subjects and found that the prevalence of α + -thalassemia was 71%. Consistent with previous observations [1, 31], we confirmed that the proportion of HbS in AS heterozygotes may be a good indicator for α + -thalassemia even in a tropical environment holoendemic for malaria. However, the determination of %HbS in AS subjects does not accurately estimate α + -thalassemia frequency, because some AS subjects with four α-globin genes also had low %HbS.…”

Section: Discussionsupporting

confidence: 80%

α-Thalassemia in Bantu Population from Congo-Brazzaville: Its Interaction with Sickle Cell Anemia

et al. 1999

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Deletional α⁺-thalassemia (–α^3.7) was investigated in four groups of unrelated individuals from the Bantu population (newborns, normal adults, sickle cells trait carriers, sickle cell anemia patients) of Brazzaville, Congo. The frequency of the (–α^3.7) chromosome was similar between newborns (f = 0.40) and adult subjects (f = 0.36), and between sicklers and nonsickler subjects. The frequency of the (–α^3.7) chromosome in sickle cell anemia patients (SS patients) did not change when age was stratified. The hematological characteristics of SS patients with (–α/αα, –α/–α) and without (αα/αα) α⁺-thalassemia were similar to those reported in Jamaican and US sickle cell anemia patients. α⁺-Thalassemia had an effect on the percentage of hemoglobin S in sickle cell trait carriers. Thus, the high frequency of α⁺-thalassemia in the Congolese population presumably results from this disorder having a selective advantage favoring survival. However, the frequency of α⁺-thalassemia was not affected by age. Although in this selective tropical environment, α⁺-thalassemia as elsewhere markedly affects the hematological characteristics of sickle cell anemia patients, however our data provide no evidence that α⁺-thalassemia increases survival of SS patients.

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Section: Discussionsupporting

confidence: 80%

α-Thalassemia in Bantu Population from Congo-Brazzaville: Its Interaction with Sickle Cell Anemia

et al. 1999

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“…For example, observation of the nature of sickle cell anemia in several individuals who have also inherited a-thalassemia trait has suggested in some cases (4-6), but not all (7,8), a favorable effect of the athalassemia gene on the clinical severity of sickle cell anemia. a-Thalassemia with sickle cell trait consistently results in a lower than usual percentage ofhemoglobin (Hb)S (9)(10)(11)(12)(13). We have investigated a child with sickle trait and microcytic anemia whose Asian mother had a-thalassemia trait and whose Black father had sickle trait.…”

Section: Introductionmentioning

confidence: 99%

Modification of Hemoglobin H Disease by Sickle Trait

Matthay¹,

Mentzer²,

Dozy³

et al. 1979

J. Clin. Invest.

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A B S T R A C T The rarity of hemoglobin (Hb) H disease in combination with sickle trait may be due in part to the absence ofactual Hb H in individuals who, nonetheless, have inherited the deletion of three a-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 a/non-a globin chain synthesis ratio was 0.58 at age 5. The mother (Asian) had laboratory evidence of a-thalassemia trait and the father (Black) had sickle trait. The nature of a-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 a-globin structural gene identified by hybridization with complementary DNA. The patient had only one a-globin structural gene, located in a DNA fragment shorter than that found in normal or a-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(A available for Hb H formation (since one 8-globin gene is (3s) and the greater affinity of a-chains for (3A than 8s-globin chains leading to the formation of relatively more Hb A than Hb S. The pres-

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“…This is caused by the interaction of HbAS with a-thalassemia (14,(16)(17)(18). Gene-deletion a-thalassemia is common in blacks.…”

Section: Introductionmentioning

confidence: 99%

Effects of alpha-thalassemia and sickle polymerization tendency on the urine-concentrating defect of individuals with sickle cell trait.

Gupta¹,

Kirchner²,

Nicholson³

et al. 1991

J. Clin. Invest.

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A defect in urine concentrating ability occurs in individuals with sickle cell trait (HbAS). This may result from intracellular polymerization of sickle hemoglobin (HbS) in erythrocytes, leading to microvascular occlusion, in the vasa recta of the renal medulla. To test the hypothesis that the severity ofthe concentrating defect is related to the percentage of sickle hemoglobin present in erythrocytes, urinary concentrating ability was examined after overnight water deprivation, and intranasal desmopressin acetate (dDAVP) in 27 individuals with HbAS. The HbAS individuals were separated into those who had a normal a-globin genotype (aa/aa), and those who were either heterozygous (-a/aa) or homozygous (-a/-a) for gene-deletion a-thalassemia, because a-thalassemia modulates the HbS concentration in HbAS. The urinary concentrating ability was less in the aa/aa genotype than in the -a/aa or -a/-a genotypes (P < 0.05). After dDAVP, the urine osmolality was greater in patients with the -a/-a genotype than with the -a/aa genotype (882±37 vs. 672±38 mOsm/kg H20) (P < 0.05); patients with the -a/aa genotype had greater concentrating ability than individuals with a normal a-globin gene arrangement. There was an inverse linear correlation between urinary osmolality after dDAVP and the percentage HbS in all patients studied (r = -0.654; P < 0.05). A linear correlation also existed for urine concentrating ability and the calculated polymerization tendencies for an oxygen saturation of 0.4 and 0 (r = -0.62 and 0.69, respectively). We conclude that the severity of hyposthenuria in HbAS is heterogeneous. It is determined by the amount of HbS polymer, that in turn is dependent upon the percentage HbS, which is itself related to the a-globin genotype. (J. Clin.

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Alpha Thalassaemia in Adults with Sickle‐Cell Trait

Cited by 62 publications

References 23 publications

α-Thalassemia in Bantu Population from Congo-Brazzaville: Its Interaction with Sickle Cell Anemia

α-Thalassemia in Bantu Population from Congo-Brazzaville: Its Interaction with Sickle Cell Anemia

Modification of Hemoglobin H Disease by Sickle Trait

Effects of alpha-thalassemia and sickle polymerization tendency on the urine-concentrating defect of individuals with sickle cell trait.

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