Regarding drug repurposing opportunities, 1 MR analysis identified interleukin-6 signaling as a potential causal risk factor of MS.35 Subsequent mediation analysis revealed that altered interleukin-6 signaling explained more than 40% of the observed effect of body mass index on MS risk.35 This example demonstrates how MR may simultaneously provide mechanistic insights for disease and identify novel causal risk factors and therapeutic targets. Here, IL6 is linked to myeloid sarcoma.