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International Journal of Hypertension
Volume 2012 (2012), Article ID 859219, 8 pages
http://dx.doi.org/10.1155/2012/859219
Research Article

Multilocus Family-Based Association Analysis of Seven Candidate Polymorphisms with Essential Hypertension in an African-Derived Semi-Isolated Brazilian Population

1Centro de Estudos do Genoma Humano and Departamento de Genética e Biologia Evolutiva, Instituto de Biociências, Universidade de São Paulo, 11461 São Paulo, SP, Brazil
2Laboratório de Genética Molecular, Departamento de Genética e Biologia Evolutiva, Instituto de Biociências, Universidade de São Paulo, SP, 11461 São Paulo, Brazil
3Instituto do Coração (InCor), Faculdade de Medicina, Universidade de São Paulo, 11461 São Paulo, SP, Brazil
4Departamento de Pediatria, Instituto da Criança, Hospital das Clínicas, Faculdade de Medicina, Universidade de São Paulo, 11461 São Paulo, SP, Brazil

Received 9 May 2012; Accepted 11 July 2012

Academic Editor: Monica Domenech

Copyright © 2012 L. Kimura et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Background. It has been widely suggested that analyses considering multilocus effects would be crucial to characterize the relationship between gene variability and essential hypertension (EH). Objective. To test for the presence of multilocus effects between/among seven polymorphisms (six genes) on blood pressure-related traits in African-derived semi-isolated Brazilian populations (quilombos). Methods. Analyses were carried out using a family-based design in a sample of 652 participants (97 families). Seven variants were investigated: ACE (rs1799752), AGT (rs669), ADD2 (rs3755351), NOS3 (rs1799983), GNB3 (rs5441 and rs5443), and GRK4 (rs1801058). Sensitivity analyses were further performed under a case-control design with unrelated participants only. Results. None of the investigated variants were associated individually with both systolic and diastolic BP levels (SBP and DBP, respectively) or EH (as a binary outcome). Multifactor dimensionality reduction-based techniques revealed a marginal association of the combined effect of both GNB3 variants on DBP levels in a family-based design ( ), whereas a putative NOS3-GRK4 interaction also in relation to DBP levels was observed in the case-control design only ( ). Conclusion. Our results provide limited support for the hypothesis of multilocus effects between/among the studied variants on blood pressure in quilombos. Further larger studies are needed to validate our findings.