Objective: The objectives were to identify quantitative trait loci linked to serum adiponectin concentration and to estimate heritability in two populations of African descent.
Research methods and procedures: We conducted a genome scan for serum adiponectin concentration in two populations of African descent. Genome-wide microsatelitte markers were typed in an African-American population consisting of 203 families from the Chicago area and in a Nigerian Yoruba population consisting of 146 families. Linkage analysis was performed to identify loci. Variance component model was used to estimate heritability.
Results: Estimates of heritability adjusted for age, gender, and BMI were 0.45 and 0.70 for the African-American and Nigerian families, respectively. In both populations, adiponectin was significantly negatively correlated with BMI, height, and weight. After adjusting for age, gender, and BMI, we found evidence of genetic linkage to adiponectin on chromosomes 11 [limit of detection (LOD) score = 2.89] and 17 (LOD score = 1.35) in the Nigerian sample. Among the African-Americans, we found genetic linkage on chromosomes 2 (LOD score = 1.82), 4 (LOD score = 2.12), and 11 (LOD score = 2.33). Analysis based on combined data yielded a maximum LOD score of 3.21 on chromosome 11.
Discussion: Consistency of the finding on chromosome 11 suggests that this region is likely to be involved in regulation of adiponectin, either through a primary influence on hormone levels or through pathways influencing body composition. These results suggest that adiponectin could be a potential therapeutic target for obesity.