APOA5 polymorphisms associated with lipid metabolism in Brazilian children and adolescents.

Single nucleotide polymorphisms in the APOA5 gene have been studied for their association with metabolic syndrome. Thus, elucidating the effect of the mechanism involved in APOA5 gene polymorphisms on lipid metabolism is of great importance. In this study we aimed to determine the allelic and genotypic frequencies of -1131T>C, Ser19Trp, and intergenic APOA4/A5 and to evaluate the association between these variants with plasma lipid levels in children and adolescents from Brazil. This study included 524 healthy children and adolescents from Mother and Child Hospital in Recife, Pernambuco, Brazil. Data were obtained on medical history, drug intake, lifestyle variables, and demography. DNA from collected samples was extracted and genotyped for the three polymorphisms. In this studied population, triglycerides and very low-density protein levels were significantly high in subjects carrying the 19WW genotype (P < 0.001), demonstrating the presence of this genetic risk factor in children and adolescents.

Mitochondrial DNA and Alu insertions in a genetically peculiar population: the Ayoreo Indians of Bolivia and Paraguay.

A total of 91 Ayoreo individuals previously studied for blood groups and protein markers, living in two Bolivian and one Paraguayan communities, were extensively investigated in relation to the hypervariable 1 segment of the control and eight coding regions of their mitochondrial DNA (mtDNA). They show an extremely reduced mtDNA variability, the observed haplotypes being classifiable in just two haplogroups (C and D). They were also variously studied in relation to six Alu insertions; in this case, however, the prevalences found did not depart markedly from those obtained in other populations of this ethnic group. To assess the Ayoreo position in relation to these populations, 11 other groups that had also been studied for these systems and for blood groups and proteins were selected. The dendrograms obtained with two of the three sets of markers showed distinct patterns, but the Ayoreo were placed in a central position in both the blood group + proteins and Alu insertions trees. Therefore, they are clearly distinct in relation to their mtDNA only, suggesting a strong founder effect and/or random loss of variability in this system.

Genetics, surnames, grandparents' nationalities, and ethnic admixture in Southern Brazil: do the patterns of variation coincide?

A total of 2,708 individuals from the European-derived population of Rio Grande do Sul, divided into seven mesoregions, and of 226 individuals of similar origin from Santa Catarina were studied. Seventeen protein genetic systems, as well as grandparents' nationalities, individuals' surnames, and interethnic admixture were investigated. The alleles which presented the highest and lowest differences were GLO1*2 (16 per cent) and PGD*A (2 per cent), respectively, but in general no significant genetic differences were found among mesoregions. The values observed were generally those expected for individuals of European descent, with the largest difference being a lower prevalence (34-39per cent) of P*1. Significant heterogeneity among mesoregions was observed for the other variables considered, and was consistent with historical records. The Amerindian contribution to the gene pool of European-derived subjects in Rio Grande do Sul was estimated to be as high as 11 per cent. Based on the four data sets, the most general finding was a tendency for a northeast-southwest separation of the populations studied. Seven significant phenotype associations between systems were observed at the 5 per cent level (three at the 0.1 per cent level). Of the latter, the two most interesting (since they were also observed in other studies) were MNSs/Duffy and Rh/ACP.