Analysis of the CCR5 gene coding region diversity in five South American populations reveals two new non-synonymous alleles in Amerindians and high CCR5*D32 frequency in Euro-Brazilians

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%), which is the highest thus far reported for Latin America. The D32 frequency is even higher among the Euro-Brazilian Mennonites (14.2%). This allele is uncommon in Afro-Brazilians (2.0%), rare in the Guarani Amerindians (0.4%) and absent in the Kaingang Amerindians and the Oriental-Brazilians. R223Q is common in the Oriental-Brazilians (7.7%) and R60S in the Afro-Brazilians (5.0%). A29S and L55Q present an impaired response to β-chemokines and occurred in Afro- and Euro-Brazilians with cumulative frequencies of 4.4% and 2.7%, respectively. Two new non-synonymous alleles were found in Amerindians: C323F (g.3729G > T) in Guarani (1.4%) and Y68C (g.2964A > G) in Kaingang (10.3%). The functional characteristics of these alleles should be defined and considered in epidemiological investigations about HIV-1 infection and AIDS incidence in Amerindian populations

Valongo, genetic studies on an isolated Afro-Brazilian community

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%), 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% ± 10.41 of A alleles and 2.67% ± 10.41 of E alleles

cystic fibrosis mutations r1162x and 2183aa g in two southern brasilian states

We screened 79 southern Brazilian patients with cystic fibrosis for the rare cystic fibrosis mutations R1162X and 2183AA®G. Forty-nine patients were born in the State of Paraná (PR) and 30 in the State of Santa Catarina (SC). Two 2183AA®G alleles were found among the SC patients and one among the PR patients. Six R1162X alleles were found among the SC patients and one among the PR patients. Fourteen percent of the alleles found among patients of Italian origin were R1162X, and 7% were 2183AA®G mutations. These mutations, together with DF508, were also studied in a sample of 270 normal non-related subjects of Italian origin who have been born in PR. In this sample we found two DF508 alleles and one 2183AA®G allele. DF508, R1162X and 2183AA®G frequencies were not statistically different from those observed in Italy. Our results demonstrate that it is important to include these mutations in southern Brazilian surveys of cystic fibrosis patients, especially when they are of Italian descent

Cystic fibrosis mutations R1162X and 2183AA<FONT FACE=Symbol>&reg;</FONT>G in two southern Brasilian states

We screened 79 southern Brazilian patients with cystic fibrosis for the rare cystic fibrosis mutations R1162X and 2183AA<FONT FACE="Symbol">&reg;</FONT>G. Forty-nine patients were born in the State of Paraná (PR) and 30 in the State of Santa Catarina (SC). Two 2183AA<FONT FACE="Symbol">&reg;</FONT>G alleles were found among the SC patients and one among the PR patients. Six R1162X alleles were found among the SC patients and one among the PR patients. Fourteen percent of the alleles found among patients of Italian origin were R1162X, and 7% were 2183AA<FONT FACE="Symbol">&reg;</FONT>G mutations. These mutations, together with <FONT FACE="Symbol">D</FONT>F508, were also studied in a sample of 270 normal non-related subjects of Italian origin who have been born in PR. In this sample we found two <FONT FACE="Symbol">D</FONT>F508 alleles and one 2183AA<FONT FACE="Symbol">&reg;</FONT>G allele. <FONT FACE="Symbol">D</FONT>F508, R1162X and 2183AA<FONT FACE="Symbol">&reg;</FONT>G frequencies were not statistically different from those observed in Italy. Our results demonstrate that it is important to include these mutations in southern Brazilian surveys of cystic fibrosis patients, especially when they are of Italian descent.<br>Realizou-se a análise de 79 pacientes provenientes do Sul do Brasil para duas mutações raras da fibrose cística (CF), R1162X e 2183AA<FONT FACE="Symbol">&reg;</FONT>G; dentre estes pacientes, 49 eram nascidos no Estado do Paraná (PR) e 30 eram nascidos no Estado de Santa Catarina (SC). Para a mutação 2183AA<FONT FACE="Symbol">&reg;</FONT>G, dois alelos foram detectados entre os pacientes de SC e um alelo nos pacientes de PR. Para a mutação R1162X, seis 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% dos alelos detectados entre os pacientes de origem italiana eram portadores da mutação R1162X e 7% da mutação 2183AA<FONT FACE="Symbol">&reg;</FONT>G. Estas mutações, juntamente com a mutação <FONT FACE="Symbol">D</FONT>F508, também foram analisadas em uma amostra de 270 indivíduos normais de origem italiana não-consangüíneos, os quais eram nascidos no Estado do PR. Nessa amostra foram detectados dois alelos <FONT FACE="Symbol">D</FONT>F508 e um alelo 2183AA<FONT FACE="Symbol">&reg;</FONT>G. As freqüências das mutações <FONT FACE="Symbol">D</FONT>F508, R1162X e 2183AA<FONT FACE="Symbol">&reg;</FONT>G não mostraram desvio estatístico significativo daquelas freqüências observadas no norte da Itália. Nossos resultados demonstram que é importante incluir estas mutações no conjunto de mutações a serem pesquisadas nos pacientes com FC do sul do Brasil, especialmente quando estes pacientes tiverem origem italiana

Cystic Fibrosis in the Brazilian Population: DF508 Mutation and KM-19/XV-2C Haplotype Distribution

We have used PCR amplification of DNA obtained from Guthrie cards to identify the DF508 mutation and correlate it with the allele frequencies at two polymorphic loci (XV-2C and KM- 19) closely linked to the cystic fibrosis gene. The DNA came from 193 white Brazilian families affected by cystic fibrosis and living in five different states of Brazil. The distribution of the haplotypes derived from the DF508 and non-DF508 XV-2C/KM-19 genotypes indicates that 88% of the DF508 alleles are linked to haplotype В and suggests that high heterogeneity exists among the non-DF508 cystic fibrosis alleles occurring in different states. Our data can be used to compare linkage disequilibrium between Brazilians and other heterogeneous populations where the DF508 mutation frequency is low and where many different rare mutations account for the remaining recessive cystic fibrosis alleles