C3 (Woroniecka Diabetes Glom GSE30528 [23] p = 0.005, rs = −0.580; Woroniecka Diabetes TubInt GSE30529 [23] p = 8.95 × 10−7, rs = −0.842; Schmid Diabetes TubInt [34] p= 0.046, rs = −0.611) and IGHM (Woroniecka Diabetes Glom GSE30528 [23] p = 0.003, rs = −0.604 and Woroniecka Diabetes TubInt GSE30529 [23] p = 8.15 × 10−5, rs = −0.740) mRNA levels in renal tubular and glomerular tissue were negatively correlated with eGFR in human patients with DKD, suggesting that increased C3 and IGHM expression is linked to reduced renal function. This evidence concerns the gene C3 and diabetic kidney disease.