RSPO3 and type 2 diabetes mellitus: Moreover, to estimate the impact of RSPO3 protein level on type 2 diabetes and fracture risk, we used the top SNP at rs4580892, a cis-pQTL for circulating RSPO3 (p=2.34  ×  10−11) identified by Sun et al in an independent dataset (Sun et al., 2018), to instrument the circulating protein level of RSPO3.