Heterogeneous Distribution of HbS and HbC Alleles in Afro-derived Brazilian Populations

Oliveira, Silviene Fabiana de; Pedrosa, Maria Angélica F.; Sousa, Sandra Maria Zákia Lian; Mingroni‐Netto, Regina Célia; Abe‐Sandes, Kiyoko; Ferrari, Íris; Barbosa, Ana Angélica Leal; Auricchio, Maria Teresa B.M.; Klautau‐Guimarães, Maria de Nazaré

doi:10.31901/24566330.2002/02.03.02

Cited by 4 publications

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“…The low frequency of HBB*S genes observed in Saracura (0.9%), although similar to that in the Afro-descendants (quilombo remnants) of Cametá (0.5%) and Itamoari (0%) counties, Pará State, is significantly lower than in the other Afro-derived communities in Trombetas (6.0%) and Pacoval (3.6%), Pará State, and Curiau (4.5%), Amapá State ( Schneider et al , 1987 ; Bortolini et al , 1992 ; Guerreiro et al , 1999 ; Oliveira et al , 2002 ). The distribution of hemoglobin S in Afro-Brazilian communities from other regions in the northeast, midwest, southeast and south, is also heterogeneous.…”

Section: Discussionmentioning

confidence: 58%

“…On the other hand, even though absence of the HBB*C allele has also been reported in most of the Afro-Amazonian communities so far studied, in Curiau frequency was 6.2%. Although this particular variant is also absent in most of the Afro-Brazilian communities from other regions, it occurred in at least one in each ( Oliveira et al , 2002 ; Auricchio et al , 2007 ). As remnant quilombo populations are generally small, the occurrence of genetic drift and/or founder effect, as well as admixture with individuals of European and Amerindian ancestry could explain this heterogeneous distribution of the HBB*S and HBB*C alleles among these populations.…”

Section: Discussionmentioning

confidence: 85%

“…From genetic studies undertaken in populations of African descent, the level of isolation and mobility has been evaluated, and the gene contribution from other sources quantified. Briefly, the genetic variability observed in these communities is consistent with their African origin, with some degree of local differentiation and admixture with individuals of Caucasian and/or Amerindian ancestry (Bortolini et al , 1987; Guerreiro et al , 1999 ; Oliveira et al , 2002 ).…”

Section: Introductionmentioning

confidence: 88%

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Inherited hemoglobin disorders in an Afro-Amazonian community: Saracura

2012

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The most common hemoglobinopathies, viz, hemoglobins S and C, and α- and β-thalassemias, were investigated through the molecular screening of 116 subjects from the community of Saracura, comprising fugitive African slaves from farms of the municipality of Santarém, in the west of Pará State, Brazilian Amazon. The observed frequency of the HBB*S gene (0.9%) was significantly lower than that encountered in other Afro-derived communities in the region. Concomitantly, the absence of the HBB*C allele has been reported for most of the Afro-Amazonian communities thus far studied. As remnant populations of quilombos are generally small, the heterogeneous distribution of HBB * S and HBB * C alleles among them is probably due to genetic drift and/or founder effect. The observed frequency of 3.7 kb deletion in Saracura (8.5%) was consistent with the African origin of the population, with a certain degree of local differentiation and admixture with individuals of Caucasian ancestry, placed in evidence by the occurrence of - -(MED) deletion (1.2%), a common mutation in Mediterranean regions. As regards β-thalassemia, among the seven different mutations found in Saracura, three β o and two β + mutations were of Mediterranean origin, and two β + of African. Thus, only 28% of the local β-thalassemia mutations found in Saracura were of African origin.

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Section: Discussionmentioning

confidence: 58%

Section: Discussionmentioning

confidence: 85%

Section: Introductionmentioning

confidence: 88%

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Inherited hemoglobin disorders in an Afro-Amazonian community: Saracura

2012

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“…This high frequency is expected in afro-descendent populations, but it is lower than the frequency observed in most populations (from 12.4% to 40.5%) from the Cayapas River, Esmeraldas [9,10]. Compared with afro-descendent populations from other Latin American countries, Hb AS frequency from the Ambuqui population was higher than populations from Peru (5%), Colombia- (4.65%) and Costa Rica (8.2%), Uruguay (10%), Brazil (0-13%) but lower than Venezuela (19.1%) [3,6,13-15,20]. The lower frequency reported in the Ambuqui populations compared with Esmeraldas populations could be influenced by the historical origins of afro-descendant populations in Ecuador.…”

Section: Resultsmentioning

confidence: 99%

Prevalence of common hemoglobin variants in an afro-descendent Ecuadorian population

et al. 2013

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BackgroundHemoglobinopathies are among the most studied and frequent pathologies. These genetic disorders are considered a very important health care threat in many tropical countries. Ecuador is a tropical Latin-American country with an important presence of afro-descendants (7.2%). Afro-descendants are among the ethnic groups with higher frequency of hemoglobinopathies reported. Ambuqui is a region within the Imbabura province with an important presence of afro-descendants (>50%). The present study analyzed the frequency of the most common hemoglobin variants in an asymptomatic afro-descendent population using capillary electrophoresis.FindingsFrom 114 individuals, 25 (22%) reported a hemoglobin variant. All individuals that presented hemoglobin variants were heterozygotes (asymptomatic). Hemoglobin S (sickle cell trait) was the most frequent variant found (14%), followed by hemoglobin E (4.4%), Fetal (2.6%) and C (1%).ConclusionPrevalence of hemoglobin S was consistent with populations from other countries, but it was lower than other Ecuadorian afro-descendent populations. Frequency of hemoglobin C was lower than other afro-descendent populations. This data suggests the possibility of gene flow from Native American individuals to the Ambuqui population there by lowering the frequency of their hemoglobin variants compared with other afro-descendant populations. Evaluating the frequency of hemoglobinopathies in Ecuadorian populations is essential. Despite the high frequency of these disorders, very few health care facilities implement hemoglobinopathies tests as a routine practice.

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“…2) The Kalunga are an Afro-derived Brazilian group with an estimated population of 5,300. This group lives in midwestern Brazil, in a rural area of northeastern Goiás State (15° 30' S to 16° 03' S ; 47° 25' W to 48° 12' W) ( Oliveira et al , 2002 ). Historically and numerically, the Kalunga are one of the most important Brazilian Afro-derived populations known as quilombos.…”

Section: Methodsmentioning

confidence: 99%

Haptoglobin gene subtypes in three Brazilian population groups of different ethnicities

et al. 2009

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Haptoglobin is a plasma hemoglobin-binding protein that limits iron loss during normal erythrocyte turnover and hemolysis, thereby preventing oxidative damage mediated by iron excess in the circulation. Haptoglobin polymorphism in humans, characterized by the Hp*1 and Hp *2 alleles, results in distinct phenotypes known as Hp1-1, Hp2-1 and Hp2-2, whose frequencies vary according to the ethnic origin of the population. The Hp*1 allele has two subtypes, Hp *1F and Hp *1S , that also vary in their frequencies among populations worldwide. In this work, we examined the distribution frequencies of haptoglobin subtypes in three Brazilian population groups of different ethnicities. The haptoglobin genotypes of Kayabi Amerindians (n = 56), Kalunga Afro-descendants (n = 70) and an urban population (n = 132) were determined by allele-specific PCR. The Hp*1F allele frequency was highest in Kalunga (29.3%) and lowest in Kayabi (2.6%). The Hp*1F/Hp*1S allele frequency ratios were 0.6, 1.0 and 0.26 for the Kayabi, Kalunga and urban populations, respectively. This variation was attributable largely to the Hp*1F allele. However, despite the large variation in Hp*1F frequencies, results of F ST (0.0291) indicated slight genetic differentiation among subpopulations of the general Brazilian population studied here. This is the first Brazilian report of variations in the Hp*1F and Hp*1S frequencies among non-Amerindian Brazilians.

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Heterogeneous Distribution of HbS and HbC Alleles in Afro-derived Brazilian Populations

Cited by 4 publications

References 2 publications

Inherited hemoglobin disorders in an Afro-Amazonian community: Saracura

Inherited hemoglobin disorders in an Afro-Amazonian community: Saracura

Prevalence of common hemoglobin variants in an afro-descendent Ecuadorian population

Haptoglobin gene subtypes in three Brazilian population groups of different ethnicities

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