CST3 and chronic kidney disease: Of note, while the GWAS loci for the three different traits (eGFR, creatinine and cystatin C) tended to cluster independently, the loci identified for creatinine and cystatin C levels in individuals in the top percentiles (top1 and top2) were strongly correlated and clustered with loci for the creatinine GWAS in CKD patients (Fig. 3b and e).