Nevertheless, a growing body of evidence suggests that serum cystatin C levels are good predictors of all-cause mortalities [31–33]; thus, non-GFR determinants of serum cystatin C level may overlap conventional risk factors of cardiovascular diseases such as diabetes, chronic inflammation, obesity, and lower serum albumin level [34, 35]. This evidence concerns the gene CST3 and obesity due to melanocortin 4 receptor deficiency.