ABSTRACT
The CC chemokine receptor 5 (CCR5) molecule is an important co-receptor for HIV. The effect of the CCR5*D32 allele in susceptibility to HIV infection and AIDS disease is well known. Other alleles than CCR5*D32 have not been analysed before, neither in Amerindians nor in the majority of the populations all over the world. We investigated the distribution of the CCR5 coding region alleles in South Brazil and noticed a high CCR5*D32 frequency in the Euro-Brazilian population of the Paraná State (9.3 percent), which is the highest thus far reported for Latin America. The D32 frequency is even higher among the Euro-Brazilian Mennonites (14.2 percent). This allele is uncommon in Afro-Brazilians (2.0 percent), rare in the Guarani Amerindians (0.4 percent) and absent in the Kaingang Amerindians and the Oriental-Brazilians. R223Q is common in the Oriental-Brazilians (7.7 percent) and R60S in the Afro-Brazilians (5.0 percent). A29S and L55Q present an impaired response to beta-chemokines and occurred in Afro- and Euro-Brazilians with cumulative frequencies of 4.4 percent and 2.7 percent, respectively. Two new non-synonymous alleles were found in Amerindians: C323F (g.3729G > T) in Guarani (1.4 percent) and Y68C (g.2964A > G) in Kaingang (10.3 percent). The functional characteristics of these alleles should be defined and considered in epidemiological investigations about HIV-1 infection and AIDS incidence in Amerindian populations.
Subject(s)
Humans , Anti-HIV Agents , HIV Infections , /genetics , Brazil , White People , Gene Frequency , Genetic Variation , Indians, South American , Polymorphism, GeneticABSTRACT
A southern Brazilian isolated community of predominantly sub-Saharan African origin, with a total population of 74 individuals and high degree of inbreeding (F = 0.081) was studied. The small sizes of the breeding (35) and effective (21) populations, as well as the very small effective migration rate (4 percent), suggest a high probability for the occurrence of genetic drift. A sample was typed for fourteen blood genetic systems and most of these systems seem to reveal the founder effect. This evolutionary factor was probably responsible for the absence of some polymorphic alleles frequent in African populations, i.e.: ABO*B, RHD-RHCE*DCe, GPA-GPB*NS (MNSs*NS), GPA-GPB*NS U (MNSs*NSU), HBB*S, HP*2M and ESD*2. The most unusual allele frequency was that for BCHE*A, 0.27, four times higher than its highest estimated frequency and fifty times higher than that those observed in African populations. Considering the allele frequencies of the Sub-Saharan African (A) and European (E) ancestral populations, the population studied can be quantified as containing 97.33 percent ± 10.41 of A alleles and 2.67 percent ± 10.41 of E alleles.
Subject(s)
Humans , Male , Female , Child, Preschool , Child , Adolescent , Adult , Middle Aged , Brazil/ethnology , Genetics, Population , Black People , Consanguinity , Polymorphism, GeneticABSTRACT
Realizou-se a análise de 79 pacientes provenientes do Sul do Brasil para duas mutaçöes raras da fibrose cística (CF), R1162X e 2183AA G; dentre estes pacientes, 49 eram nascidos no Estado do Paraná (PR) e 30 eram nascidos no Estado de Santa Catarina (SC). Para a mutaçäo 2183AA G, dois alelos foram detectados entre os pacientes de SC e um alelo entre os pacientes do PR. Quando estes pacientes foram classificados de acordo com a origem étnica, 14 por cento dos alelos detectados entre os pacientes de origem italiana eram portadores da mutaçäo R1162X e 7 por cento da mutaçäo 2183AA G. Estas mutaçöes, juntamente com a mutaçäo delta F508, também foram analisadas em uma amostra de 270 indivíduos normais de origem italiana näo-consangüíneos, os quais eram nascidos no Estado do PR. Nessa amostra foram detectados dois alelos delta F508 e um alelo 2183AA G. As freqüências das mutaçöes delta F508, R1162X e 2183AA G näo mostraram desvio estatístico significativo daquelas freqüências observadas no norte da Itália. Nossos resultados demonstram que é importante incluir estas mutaçöes no conjunto de mutaçöes a serem pesquisadas nos pacientes com FC do sul do Brasil, especialmente quando estes pacientes tiverem origem italiana.
Subject(s)
Humans , Male , Female , Child , Adolescent , Adult , Middle Aged , White People , Cystic Fibrosis/genetics , Gene Frequency , Brazil , Genetics, Population , Mutation/genetics , Polymerase Chain ReactionABSTRACT
Estudamos uma comunidade brasileira isolada no Sul do Brasil de origem predominantemente negra, com uma populaçäo total de 81 indivíduos. O coeficiente médio de endocruzamento é igual a 0.04774, um valor que é ainda 3,5 vezes menor do que o teoricamente esperado (0,17269) se os casamentos consanguíneos ocorressem ao acaso. O coeficiente médio de endocruzamento entre os descendentes de casais consanguíneos é também muito alto, 0,06906. A freqüência de abortos é de 11,2% ñ 3,2%; a mortalidade infantil de 9,0% ñ 3,0% e os nascimentos gemelares de 2,0% ñ 1,4%. Os pequenos tamanhos das populaçöes reprodutora (28) e efetiva (15), assim como a pequena taxa de migraçäo da populaçäo reprodutora (7,1%) sugerem uma alta probabilidade para a ocorrência da deriva genética nesta populaçäo