Absence of the Δccr5 mutation in indigenous populations of the Brazilian Amazon

Leboute, Ana Paula Magalhães; Carvalho, Mônica W. P. de; Simões, Aguinaldo L.

doi:10.1007/s004390051128

Cited by 29 publications

(20 citation statements)

References 7 publications

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“…Since the CCR5∆32 allele has not been identified in Africans (Martinson et al, 1997) or Amerindians (Martinson et al, 1997;Leboute et al, 1999), the presence of the CCR5∆32 allele in Brazilians can be attributed to European immigration. The 0.053 frequency of CCR5∆32 allele that we ob-served in our sample is lower than the average frequency in Europe (0.10), reflecting the African and Amerindian contributions.…”

Section: Discussionmentioning

confidence: 99%

“…In Eurasia CCR5∆32 frequencies show a north-south gradient with the highest allele frequencies in Finnish and Mordvinian populations (16%) and the lowest in Sardinia (4%) (Libert et al, 1998). The CCR5∆32 allele is not found in aboriginal populations outside Eurasia (Martinson et al, 1997;Leboute et al, 1999;Lu et al, 1999). The presence of CCR5∆32 allele elsewhere throughout the world probably represents recent European gene flow into local populations (Martinson et al, 1997).…”

Section: Introductionmentioning

confidence: 98%

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Frequency of the CCRdelta32 allele in Brazilians: a study in colorectal cancer and in HTLV-I infection

et al. 2000

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The identification of a 32-bp deletion in the cc-chemokine receptor-5 gene (CCR5delta32 allele) that renders homozygous individuals highly resistant to HIV infection has prompted worldwide investigations of the frequency of the CCR5delta32 allele in regional populations. It is important to ascertain if CCR5delta32 is a factor to be considered in the overall epidemiology of HIV in individual populations. With this in mind we determined the CCR5delta32 allele frequency in a large sample (907 individuals) of the southeastern Brazilian urban population, stratified as follows: 322 healthy unrelated individuals, 354 unselected colorectal cancer patients, and 229 blood donors. The three groups displayed essentially identical allelic frequencies of CCR5delta32 and pairwise comparisons did not show significant differences. Thus, our results can be pooled to provide a reliable estimate of the CCR5delta32 allele frequency in the southeastern Brazil of 0.053 ± 0.005. The blood donors comprised 50 HTLV-I serologically negative individuals, 115 non-symptomatic individuals HTLV-I positive by ELISA but with indeterminate Western blot results, 49 healthy blood donors HTLV-I positive both at ELISA and Western blot and 15 patients with clinical spinal cord disease (HAM). A suggestive trend was observed, with the CCR5delta32 frequencies decreasing progressively in these four categories. However, when we applied Fischer's exact test no significant differences emerged. We believe that further studies in larger cohorts should be performed to ascertain whether the CCR5delta32 allele influences the chance of becoming infected or developing clinical symptoms of HTLV-I infection.
A observação de que indivíduos homozigotos para uma deleção de 32 pares de base no gene que codifica para o receptor 5 de cc-quimiocinas apresentam um menor risco de contrair a infecção por HIV-1 levou à investigação da freqüência deste polimorfismo em várias populações mundiais. É importante investigar se o CCR5delta32 é um fator a ser considerado na epidemiologia do HIV em populações individuais. Com estes pressupostos em mente nós estabelecemos a freqüência do CCR5delta32 em uma grande amostra (907 indivíduos não-relacionados) da população urbana do sudeste brasileiro, estratificada da seguinte maneira: 322 indivíduos sadios, 354 pacientes com câncer colorretal e 229 doadores de sangue. Os três grupos apresentaram essencialmente a mesma freqüência alélica de CCR5delta32 e a comparação par-a-par não revelou diferenças significativas. Assim, os nossos resultados podem ser agrupados para fornecer uma estimativa confiável de 0,053 ± 0,005 da freqüência alélica de CCR5delta32. Os doadores de sangue compreendiam 50 indivíduos soronegativos para HTLV-I, 115 indivíduos assintomáticos por ELISA mas com resultados indeterminados em Western blot, 49 indivíduos soropositivos para HTLV-I mas assintomáticos e 15 indivíduos soropositivos para HTLV-I sintomáticos com mielopatia. Foi observado um sugestivo gradiente decrescente da freqüência alélica de CCR5delta32 nestas cat...

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 98%

Frequency of the CCRdelta32 allele in Brazilians: a study in colorectal cancer and in HTLV-I infection

et al. 2000

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“…Calafell et al (1998,1999 Chang et al (1996); Tishkoff et al (1996aTishkoff et al ( ,b, 1998Tishkoff et al ( , 2000; Kidd et al (1998,2000); Leboute et al (1999) et al (1997, 1999, 2000); Santos et al (1998); Kaufman et al (1999) (1993); Barley et al (1994);Franco et al (1994Franco et al ( , 1996Franco et al ( , 1997; Zago et al (1996);Covas et al (1997); Marin et al (1997); Olsson et al (1998);Destro-Bistrol et al (2000); Neel (2000); 76. Mesa et al (2000); 77.…”

Section: Table VI (Continuation)mentioning

confidence: 99%

Molecular variability in Amerindians: widespread but uneven information

Salzano

2002

An. Acad. Bras. Ciênc.

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A review was made in relation to the molecular variability present in North, Central, and South American Indian populations. It involved results from ancient DNA, mitochondrial DNA in extant populations, HLA and other autosomal markers, X and Y chromosome variation, as well as data from parasitic viruses which could show coevolutionary changes. The questions considered were their origin, ways in which the early colonization of the continent took place, types and levels of the variability which developed, peculiarities of the Amerindian evolutionary processes, and eventual genetic heterogeneity which evolved in different geographical areas. Although much information is already available, it is highly heterogeneous in relation to populations and types of genetic systems investigated. Unfortunately, the present trend of favoring essentially applied research suggest that the situation will not basically improve in the future.

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“…The increase in frequency of the CCR5D32 mutant allele in a relatively short period of time could be due to selection in favor of this allele. The high frequency of the CCR5D32 allele in European populations and its virtual absence in African, Amerindian and Asian populations (Martinson et al, 1997;Leboute et al, 1999;Williamson et al, 2000;Lucotte, 2001) implies that this allele can be used as a marker of European origin. The occurrence of the CCR5D32 allele in remnant quilombo populations indicates the presence of European genes, which may have entered the gene-pool of these populations either when the populations were founded or more recently due to gene flow, although it is also conceivable that both events may have happened.…”

Section: Resultsmentioning

confidence: 99%

“…The frequency distribution of the CCR5D32 allele varies considerably between different ethnic groups, being common in Europeans (±10% frequency) but quite rare or absent (< 1%) in Asian, African and Brazilian indigenous groups (Martinson et al 1997;Leboute et al, 1999;Williamson et al, 2000;Lucotte, 2001).…”

Section: Introductionmentioning

confidence: 99%

CCR5D32 mutation in three Brazilian populations of predominantly Sub-Saharan African ancestry

et al. 2004

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This study reports the frequencies of the CCR5D32 mutation of the β-chemokine 5 gene and discusses the possible effects of past and recent gene flow in three quilombo remnants (Brazilians communities with anthropological African ancestry whose ancestors were escaped slaves): Rio das Rãs, Mocambo, and São Gonçalo in the northeastern region of Brazil. The CCR5D32 allele frequency of the Mocambo population was significantly higher (5.6%) than that found in the Rio das Rãs (1%) and São Gonçalo (0.9%) populations. These differences may reflect different proportions of parental populations in the founders individuals, a founder-effect and/or different histories of inter-ethnic contact. The frequency of the CCR5D32 allele in the Mocambo sample is similar to that found in those urban Brazilian populations which have a large amount of European genetic input, indicating a European contribution to the gene pool of this population and suggesting that, perhaps since its foundation, Mocambo has had a high level of admixture or experienced a founder-effect.

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Absence of the Δccr5 mutation in indigenous populations of the Brazilian Amazon

Cited by 29 publications

References 7 publications

Frequency of the CCRdelta32 allele in Brazilians: a study in colorectal cancer and in HTLV-I infection

Frequency of the CCRdelta32 allele in Brazilians: a study in colorectal cancer and in HTLV-I infection

Molecular variability in Amerindians: widespread but uneven information

CCR5D32 mutation in three Brazilian populations of predominantly Sub-Saharan African ancestry

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