Alpha-thalassemia is related to prolonged survival in sickle cell anemia

Mears, JG; Lachman, H.; Labie, Dominique; Nagel, RL

doi:10.1182/blood.v62.2.286.286

Cited by 68 publications

(13 citation statements)

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“…Moreover, 76% of the patients had four ␣-genes (␣␣/␣␣ genotype). The ␣-gene distribution in our pediatric patients with stroke is different than that reported in African Americans with SS at large where the prevalence of ␣␣/␣␣ genotype is about 65%, the −␣/␣␣ genotype about 30%, the −␣/−␣ genotype about 5%, and the genotype with five or more ␣-genes is <2% [8,[13][14][15]. Thus ␣-gene deletion appears to be protective against CVA in children with SS.…”

Section: Discussioncontrasting

confidence: 78%

Molecular characteristics of pediatric patients with sickle cell anemia and stroke

Sarnaik

Ballas

2001

American J Hematol

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Cerebrovascular accidents (CVA) are serious complications of sickle cell anemia (SS) in children. Factors that predispose children to this complication are not well established. In an effort to elucidate the risk factors associated with CVA in SS, we have determined the ␣-globin genotype and the ␤ S haplotype of children with this complication. Among 700 children with SS followed at Children's Hospital of Michigan, 41 (6%) are on chronic transfusions because of stroke due to cerebral infarction. The mean age of patients with CVA at the time of stroke was 5.6 ± 3.2 years (mean ± SD). The male/female ratio was 2/3. Only 8 of 41 patients (19.5%) had one ␣-gene deletion, compared to the reported prevalence of 30% in African-Americans. None of the patients had two ␣-gene deletions, and two (5%) had five ␣-genes. These findings are different than those in our adult patients with SS, where the prevalence of −␣/−␣ and ␣␣␣/␣␣ is 4% and <2%, respectively. Ten different ␤ S -haplotypes were detected in the patients studied. The majority of the patients (31%) were doubly heterozygous for the Ben/CAR haplotypes followed by Ben/Ben, Ben/ Sen, and CAR/CAR haplotypes, respectively. The prevalence of these haplotypes, with the exception of the CAR/CAR haplotype, was higher in females than males. All the patients with CAR/CAR haplotype were males, had four ␣-genes, and ranked third in prevalence. Three patients were heterozygous for the Cameron haplotype. The Cameron and atypical haplotypes were more prevalent than reported in patients with SS at large. The data suggest that CVA in children seems to occur more frequently in females and in patients with certain ␤ S haplotype. ␣-Gene deletion seems to offer a protective effect against this complication. Neonates with four or more ␣-genes whose ␤ S haplotype is Ben/CAR, atypical, or CAR/CAR seem to be at a higher risk for CAV than other patients. A prospective study on a larger group of patients with or without CVA may clarify this issue. Am.

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Section: Discussioncontrasting

confidence: 78%

Molecular characteristics of pediatric patients with sickle cell anemia and stroke

Sarnaik

Ballas

2001

American J Hematol

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“…Complications such as leg ulcers, renal pathology, and strokes are fewer, but the frequency of other complications, e.g., osteonecrosis and retinopathy, may be increased (22)(23)(24)(25). Overall survival may also be enhanced (23,26). The present study is probably the first to recognize an association of a-thal trait with preserved splenic function in SS patients with elevated HbF levels.…”

Section: Discussionmentioning

confidence: 53%

“…It decreases the rate of hemolysis by decreasing the MCHC, thereby resulting in higher Hb, Hct, and RBC values (21). Complications such as leg ulcers, renal pathology, and strokes are fewer, but the frequency of other complications, e.g., osteonecrosis and retinopathy, may be increased (22)(23)(24)(25). Overall survival may also be enhanced (23,26).…”

Section: Discussionmentioning

confidence: 99%

Influence of α-thalassemia trait on spleen function in sickle cell anemia patients with high HbF

et al. 1996

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Spleen function was studied in a group of 20 Kuwaiti SS patients (aged 2-12 years), using 99mTc-labeled tin colloid scintigraphy. They were screened for the alpha-thalassemia determinants which are prevalent in the Arabian Peninsula [-alpha (3.7 kb) deletion, alpha2-globin gene polyadenylation signal (AATAAA => AATAAG) mutation, and 5' IVS-I splice junction pentanucleotide (GAGGTGAGG => GAGG) deletion] with a combination of polymerase chain reaction and allele-specific oligonucleotide (ASO) hybridization techniques. The patients were divided into three groups depending on the result of their colloid uptake. Group I consisted of 7 patients (35.0%) with normally visualized spleens, Group II consisted of 5 (25.0%) with partial visualization, and in Group III there were 8 (40.0%) in whom the spleen was not visualized at all. The significant distinguishing features among those in Groups I and III were mean corpuscular volumes (MCVs) of 74.1 +/- 5.1 and 90.1 +/- 6.6 fl (P<0.0001) and mean corpuscular hemoglobins (MCHs) of 22.4 +/- 2.7 and 27.5 +/- 4.0 pg (P<0.05), respectively. The overall frequency of alpha-thalassemia determinants in the study was 35.0%; however, the frequencies in Groups I, II, and III were 57.1, 30.0, and 18.8%, respectively. alpha-Thalassemia trait, therefore, appears to be associated with normal splenic function in these patients.

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“…The other factor which affects clinical severity of sickle cell anemia is the coinheritance of a-thalassemia (Embury et al, 1982;Higgs et al, 1982;Mears et al, 1983). We have recently demonstrated that 22% of Brazilian sickle cell anemia patients have a deletion type a-thalassemia (Costa et al, 19891, a frequency similar to that observed in the USA and Jamaica (Dozy et al, 1979;Higgs et al, 1980).…”

Section: Studies Bymentioning

confidence: 84%

Bantu β^s cluster haplotype predominates among Brazilian Blacks

Zago

Figueiredo

Ogo

1992

American J Phys Anthropol

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We describe the combination of polymorphic restriction-enzyme sites in the beta globin gene cluster (haplotypes) for 74 chromosomes from Brazilian Blacks bearing the sickle hemoglobin gene (beta s). The three most common African beta s haplotypes account for 67 chromosomes: 49/74 (66.2%) were identified as Central African Republic (CAR or Bantu) type, 17 (23.0%) as Benin, and one as Senegal; seven chromosomes (9.5%) had minor atypical haplotypes. This distribution is different from that observed in the United States or Jamaica, where the Benin haplotype predominates, and results from different patterns of slave trades to North and South Americas. Since the beta s gene cluster polymorphisms modulate the severity of sickle cell anemia, this heterogeneity may explain differences of the clinical behavior of the disease in the United States and South America, and should also be considered in relation to other features and diseases.

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Alpha-thalassemia is related to prolonged survival in sickle cell anemia

Cited by 68 publications

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Molecular characteristics of pediatric patients with sickle cell anemia and stroke

Molecular characteristics of pediatric patients with sickle cell anemia and stroke

Influence of α-thalassemia trait on spleen function in sickle cell anemia patients with high HbF

Bantu β^s cluster haplotype predominates among Brazilian Blacks

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Alpha-thalassemia is related to prolonged survival in sickle cell anemia

Cited by 68 publications

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Molecular characteristics of pediatric patients with sickle cell anemia and stroke

Molecular characteristics of pediatric patients with sickle cell anemia and stroke

Influence of α-thalassemia trait on spleen function in sickle cell anemia patients with high HbF

Bantu βs cluster haplotype predominates among Brazilian Blacks

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Bantu β^s cluster haplotype predominates among Brazilian Blacks