rs1048201

This functional study investigated the molecular mechanism of the osteoporosis GWAS variant USF3 c.3781C>A (rs1026364), which is associated with femoral neck BMD (P=4.1×10⁻¹⁰). The authors demonstrated that the c.3781A allele creates a functional binding site for hsa-miR-345-5p, which downregulates USF3 expression and inhibits osteogenic differentiation through both USF3-dependent and independent pathways, including direct targeting of RUNX3 and SMAD1.

This is a perspective and mission statement from the GEMSTONE Consortium reviewing current and future approaches for functional validation of skeletal genetic disease using cellular, molecular, and animal-modeling techniques. The paper discusses how large GWAS have identified 518 loci associated with bone mineral density (BMD), and reviews strategies for bridging the gap between genetic association and causality through functional investigation, including the role of miRNAs (e.g., rs11614913 in MIR196A2 and rs1048201 in FGF2 3'UTR associated with lumbar spine BMD), endophenotypes, Mendelian randomization, and animal models in understanding skeletal diseases like osteoporosis.

This study identified three polymorphisms in miRNA binding sites within the FGF2 gene (rs6854081, rs1048201, rs7683093) that are significantly associated with femoral neck bone mineral density in 997 discovery and 1,728 replication subjects. Linear regression analyses showed that rs6854081 had consistent associations across both cohorts (p=8.37E-03 and p=5.79E-02), and independent gene expression analyses confirmed reduced FGF2 expression in subjects with high versus low BMD, supporting a regulatory mechanism through altered miRNA binding.