Two novel pleiotropic loci associated with osteoporosis and abdominal obesity

Aiming to uncover a shared genetic basis of abdominal obesity and osteoporosis, we performed a bivariate GWAS meta-analysis of femoral neck BMD (FNK-BMD) and trunk fat mass adjusted by trunk lean mass (TFM adj ) in 11,496 subjects from 6 samples, followed by in silico replication in the large-scale UK Biobank (UKB) cohort. A series of functional investigations were conducted on the identified variants. Bivariate GWAS meta-analysis identified two novel pleiotropic loci 12q15 (lead SNP rs73134637 , p = 3.45 × 10 –7 ) and 10p14 (lead SNP rs2892347 , p = 2.63 × 10 –7 ) that were suggestively associated and that were replicated in the analyses of related traits in the UKB sample (osteoporosis p = 0.06 and 0.02, BMI p = 0.03 and 4.61 × 10 –3 , N up to 499,520). Cis -eQTL analysis demonstrated that allele C at rs73134637 was positively associated with IFNG expression in whole blood ( N = 369, p = 0.04), and allele A at rs11254759 (10p14, p = 9.49 × 10 –7 ) was negatively associated with PRKCQ expression in visceral adipose tissue ( N = 313, p = 0.04) and in lymphocytes ( N = 117, p = 0.03). As a proof-of-principle experiment, the function of rs11254759 , which is 235 kb 5′-upstream from PRKCQ gene, was investigated by the dual-luciferase reporter assay, which clearly showed that the haplotype carrying rs11254759 regulated PRKCQ expression by upregulating PRKCQ promoter activity ( p = 4.60 × 10 –7 ) in an allelic specific manner. Mouse model analysis showed that heterozygous PRKCQ deficient mice presented decreased fat mass compared to wild-type control mice ( p = 3.30 × 10 –3 ). Mendelian randomization analysis demonstrated that both FNK-BMD and TFM adj were causally associated with fracture risk ( p = 1.26 × 10 –23 and 1.18 × 10 –11 ). Our findings may provide useful insights into the genetic association between osteoporosis and abdominal obesity.