SMR was demonstrated that it was useful to prioritize novel genes associated with BMD. There was no GWAS signal within 0.5 Mb of the probe in SYN2 (Fig. 1B). However, by the SMR tests, our study identified significant association signal for SYN2. SMR tests reduced the multiple hypothesis burdens by testing tens of thousands of genes instead of millions of SNPs [17]. The synapsins are a family of 4 synaptic vesicle-associated proteins which are products from alternative splicing of two genes, SYN1 and SYN2. The previous study which showed that the release of glutamate via synapsin can directly promote osteoblast differentiation [57], suggesting that SYN2 played an important role in osteoblast differentiation.
