Of the 6 SNPs associated with serum magnesium concentrations, rs7965584 (near ATP2B1) was statistically significantly associated with all ischemic stroke, large artery stroke, and small vessel stroke; rs4072037 (MUC1) was associated with cardioembolic stroke; and rs448378 (MDS1) was associated with large artery stroke (data available from Open Science Framework, table 2 and figure e-1, osf.io/b57sq/). The gene discussed is ATP2B1; the disease is small vessel stroke.