A genome-wide bivariate analysis was conducted for body fat mass (BFM) and bone mineral density (BMD) in a large Caucasian sample. We found some quantitative trait loci (QTLs) shared by BFM and BMD in the total sample and the gender-specific subgroups, and QTLs with potential pleiotropy were disclosed.

Introduction: BFM and BMD, as the respective measure for obesity and osteoporosis, are phenotypically and genetically correlated. However, specific genomic regions accounting for their genetic correlation are unknown.

Materials and Methods: To systemically identify the shared genomic regions for BFM and BMD, we performed a bivariate whole-genome linkage scan (WGLS) in 4498 Caucasian individuals from 451 families for BFM and BMD at the hip, spine, and wrist respectively. Linkage analyses were performed in the total sample and in the male and female subgroups, respectively.

Results: In the entire sample, suggestive linkages were detected at 7p22-p21 (LOD=2.69) for BFM & spine BMD, 6q27 (LOD=2.30) for BFM & hip BMD, and 11q13 (LOD=2.64) for BFM & wrist BMD. Male-specific suggestive linkages were found at 13q12 (LOD=3.23) for BFM & spine BMD and at 7q21 (LOD=2.59) for BFM & hip BMD. Female-specific suggestive LOD scores were 3.32 at 15q13 for BFM & spine BMD, and 3.15 at 6p25-24 for BFM & wrist BMD.

Conclusions: Several shared genomic regions for BFM and BMD were identified here. Our data may benefit further positional and functional studies, aiming at eventually uncovering the complex mechanism underlying the shared genetic determination of obesity and osteoporosis.