CRP and coronary artery disorder: Estimating the causal influence of CRP on CHD (69,70) is likely to be quite susceptible to this problem, using all 20 variants from Dehghan et al. (68) in an IVW estimate suggests a fairly strong protective effect −0.13 (S.E.=0.064), but the CRP variant rs2794520 alone gives a much flatter result of 0.009 (S.E.=0.061), consistent with previous analyses (see Appendix 2 for R code on how to obtain these results in MR-Base) (8).