After removing linkage disequilibrium and weak instrumental variables, 64, 64, 10, 10, 64, 50, 57, 62, 62, 18, 65 and 43 SNPs associated with mtDNA-CN were selected from the GWAS database of ARF, CKD, CKDi25, Rapid3, RD, eGFR, BUN, UACR, MAU, CysC, NGAL and KIM-1 (Supplementary Table S1). Here, LCN2 is linked to chronic kidney disease.