Several studies have demonstrated that tubular involvement may precede glomerular involvement, leading to an increase of various serum and urinary markers, including glomerular-transferrin, fibronectin, beta-2 microglobulin (β2M), retinol binding protein, alpha-1 microglobulin, ephrin-B2, annexin A7, paternally expressed 10 (PEG10), cystatin C, tammhorsfall protein, beta 2 glycoprotein-1, urinary enzymes (N-acetyl-beta-D-glucosaminidase, choline-sterase, gamma glutamyltranspeptidase, alanine amino-peptidase), and tubular brush-border antigen, following diabetic nephropathy.3-7. The gene discussed is B2M; the disease is diabetic kidney disease.