The observed alterations in FGF-2, FGF-19, FGF-22, and FGF-23 concentrations—particularly their associations with hypertension, obesity, nephropathy, and joint degeneration—support their role not only in the pathogenesis but also in the clinical stratification of diabetic complications. This evidence concerns the gene FGF19 and obesity due to melanocortin 4 receptor deficiency.