However, among the Mayo Clinic CKD patients--in contrast to what was observed in the CKD populations of CRIC, MDRD and AASK--the ratio of CrCl/iGFR were progressively larger with lower CrCl level (Table 2, Fig. 1b) (details in Additional file 1: Table S3_1B). This evidence concerns the gene IGF1R and chronic kidney disease.