When using these variants as instruments in Mendelian randomisation, the genetically proxied TYK2 expression was associated with the risk of type 1 diabetes (rs2304256: OR 0.61 [95% CI 0.54, 0.69]) whereas we found no clear evidence for association when using missense variants in IL6ST (OR 0.98 [95% CI 0.78, 1.20]) or JAK2 (OR 0.74 [95% CI 0.46, 1.20]; Table 3). Here, IL6ST is linked to type 1 diabetes mellitus.