However, a recent study suggested that the association between BMI and BNP and NT-proBNP could be mediated by lean mass rather than fat mass (Das et al. 2005), and these results do not support the hypothesis that the lower BNP levels seen in obesity are driven by enhanced BNP clearance mediated via NPR-C. Here, NPPB is linked to obesity due to melanocortin 4 receptor deficiency.