IL1RL2 and small vessel stroke: ABO Univariate MR of multiple cohorts revealed that the risk of small vessel stroke (SVS) increases with elevated levels of TNF‐related apoptosis‐inducing ligand (TRAIL, OR, 1.23, 95% CI, 1.08–1.39) and interleukin‐1 receptor‐like 2, (IL‐1RL2, OR, 1.29, 95% CI, 1.04–1.61).