Ancestry informative markers and complete blood count parameters in Brazilian blood donors

Félix, Gabriela; Abe‐Sandes, Kiyoko; Bonfim, Taísa M.; Bendicho, Maria Teresita; Cisneiros, Patrícia; Guedes, Rosalina; Brandão, Claudio; Torres, Alex José Leite; Brites, Carlos; Netto, Eduardo Martins; Meyer, Roberto; Freire, Songelí Menezes

doi:10.1590/s1516-84842010005000074

Cited by 10 publications

(6 citation statements)

References 9 publications

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“…Further analyses sampling the population of Salvador using autosomal markers and mitochondrial DNA estimated the largest ancestral contribution to be African, followed by European and Amerindian Felix et al, 2010). Thus, the current results from an all-male sample indicate that Bahia's southern region presents an ethnic admixture moderately different from that found in the capital.…”

Section: Discussionmentioning

confidence: 51%

Self-declared ethnicity and genomic ancestry in prostate cancer patients from Brazil

et al. 2016

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ABSTRACT. Some studies of polymorphisms in prostate cancer (PCa) analyze individuals in a uniform manner, regardless of genetic ancestry. However, PCa aggressiveness differs between subjects of African descent and those of European extraction. Thus, genetic ancestry analysis may be used to detect population stratification in case-control association studies. We genotyped 11 ancestry informative markers to estimate the contributions of African, European, and Amerindian ancestries in a case-control sample of 213 individuals from Bahia State, Northeast Brazil, including 104 PCa patients. We compared this data with self-reported ancestry and the stratification of cases by PCa aggressiveness according to Gleason score. A larger African genetic contribution (44%) was detected among cases, and a greater European contribution (61%) among controls. Self-declaration data revealed that 74% of PCa patients considered themselves non-white (black and brown), and 41.3% of controls viewed themselves as white. Our data showed a higher degree of European ancestry among fast-growing cancer cases than those of intermediate and slow development. This differs from many previous studies, in which the prevalence of African ancestry has been reported for all grades. Differences were observed between degrees of PCa aggressiveness in terms of genetic ancestry. In particular, the greater European contribution among patients with highgrade PCa indicates that a population's genetic structure can influence case-control studies. This investigation contributes to our understanding of the genetic basis of tumor aggressiveness among groups of different genetic ancestries, especially admixed populations, and has significant implications for the assessment of inter-population heterogeneity in drug treatment effects.

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Section: Discussionmentioning

confidence: 51%

Self-declared ethnicity and genomic ancestry in prostate cancer patients from Brazil

et al. 2016

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“…The small contribution of indigenous ancestry to the makeup of the population of Salvador has also been documented elsewhere. 31 The differences observed in Ancestry estimates for Fortaleza and Salvador using different African pseudoancesters may represent differences in the origins of African populations arriving at these two ports. 32,33 In fact, Salvador received slaves coming from a large area of West Africa, whereas Fortaleza received slaves mostly from Angola, Congo and Mozambique.…”

Section: Discussionmentioning

confidence: 99%

The correlation between ancestry and color in two cities of Northeast Brazil with contrasting ethnic compositions

et al. 2014

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The degree of admixture in Brazil between historically isolated populations is complex and geographically variable. Studies differ as to what the genetic and phenotypic consequences of this mixing have been. In Northeastern Brazil, we enrolled 522 residents of Salvador and 620 of Fortaleza whose distributions of self-declared color were comparable to those in the national census. Using the program Structure and principal components analysis there was a clear correlation between biogeographic ancestry and categories of skin color. This correlation with African ancestry was stronger in Salvador (r=0.585; P<0.001) than in Fortaleza (r=0.236; P<0.001). In Fortaleza, although self-declared blacks had a greater proportion of European ancestry, they had more African ancestry than the other categories. When the populations were analyzed without pseudoancestors, as in some studies, the relationship of 'race' to genetic ancestry tended to diffuse or disappear. The inclusion of different African populations also influenced ancestry estimates. The percentage of unlinked ancestry informative markers in linkage disequilibrium, a measure of population structure, was 3-5 times higher in both Brazilian populations than expected by chance. We propose that certain methods, ascertainment bias and population history of the specific populations surveyed can result in failure to demonstrate a correlation between skin color and genetic ancestry. Population structure in Brazil has important implications for genetic studies, but genetic ancestry is irrelevant for how individuals are treated in society, their health, their income or their inclusion. These track more closely with perceived skin color than genetic ancestry.

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“…Little is known about the genetic susceptibility to breast cancer of African-descended Brazilian women, an understudied population. As there is a high degree of genetic admixture among Brazilian populations [22][23][24], we sought to study the genetic susceptibility to breast cancer in one of the largest Africandescended populations in Latin America, the inhabitants of the State of Bahia in the Northeast region of Brazil.…”

Section: Discussionmentioning

confidence: 99%

Mutational Spectrum of Breast Cancer Susceptibility Genes among Women in Northeast Brazil

Félix

Guindalini

Zheng

et al. 2021

Preprint

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Purpose: There is a paucity of data on the spectrum and prevalence of pathogenic variants among women of African ancestry in the Northeast region of Brazil. Methods: We performed BROCA panel sequencing to identify inherited loss-of-function variants in breast cancer susceptibility genes among 292 Brazilian women referred to a single institution cancer risk assessment program. Results: The study included a convenient cohort of 173 women with invasive breast cancer and 119 women who were cancer-free at the time of ascertainment. The majority of the women self-reported as African-descended (67% for cases and 90.8% for controls). Thirty-seven pathogenic variants were found in 36 (20.8%) patients. While the spectrum of pathogenic variants was heterogeneous, the majority (70.3%) of the pathogenic variants were detected in high-risk genes BRCA1 , BRCA2 , PALB2 , and TP53 . Pathogenic variants were also found in the ATM , BARD1 , BRIP1 , FAM175A , FANCM , NBN , and SLX4 genes in 6.4% of the affected women. Four recurrent pathogenic variants were detected in 11 patients of African ancestry. Only one unaffected woman had a pathogenic variant in the RAD51C gene. Conclusion: The high prevalence and heterogenous spectrum of pathogenic variants identified among self-reported African descendants in Northeast Brazil is consistent with studies in other African populations with a high burden of aggressive young onset breast cancer. It underscores the need to integrate comprehensive cancer risk assessment and genomic testing in the management of newly diagnosed Black women with breast cancer across the African Diaspora, enabling improved cancer control in admixed underserved and understudied populations.

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Ancestry informative markers and complete blood count parameters in Brazilian blood donors

Abstract: Afro-Americans, another admixed population. Rev. Bras. Hematol. Hemoter. 2010;32(4):282-285.

Cited by 10 publications

References 9 publications

Self-declared ethnicity and genomic ancestry in prostate cancer patients from Brazil

Self-declared ethnicity and genomic ancestry in prostate cancer patients from Brazil

The correlation between ancestry and color in two cities of Northeast Brazil with contrasting ethnic compositions

Mutational Spectrum of Breast Cancer Susceptibility Genes among Women in Northeast Brazil

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