Genetic effects on blood pressure localized to chromosomes 6 and 7

Objective To identify quantitative trait loci (QTL) contributing to the variation in blood pressure in a west African population. Methods We conducted a multi-stage genome scan in a population sample from rural Nigeria. A 10 centimorgan genome-wide screen for log-transformed systolic blood pressure (SBP) and diastolic blood pressure (DBP) was first performed based on 1054 individuals from 188 families. In the second phase we performed a similar analysis in an independent sample of 621 individuals from 101 families. In a third follow-up fine mapping phase we genotyped 25 additional markers in the three regions identified in the first two phases. Results Genome-wide significant linkage evidence was found for SBP on chromosome 7p (lod = 4.73, genome wide P <= 0.01, point-wise P = 1.53 X 10(-6)) in the combined sample. Suggestive linkage evidence was also detected on 6q (lod = 2.9, point-wise P = 0.00013) and 7q (lod = 2.6, point-wise P = 0.00027) for SBP, and 7q (lod = 1.6, point-wise P = 0.003) for DBP. Conclusions This study has identified several regions that may harbor genetic variants affecting the variation in blood pressure. Further association mapping under the linkage peaks will be required to refine the linkage evidence that has emerged from our analysis. (c) 2005 Lippincott Williams & Wilkins.