LPL and obesity due to melanocortin 4 receptor deficiency: The novelty of the approach we used is that it provided a set of peptides from Apo CIII, Apo A1, Apo B100, LPL, AACT, CC3 to be targeted in patients adopting MS methods based on absolute quantification through a single-reaction-monitoring (SRM) approach35,36, possibly allowing to identify disease specific patterns that can be translated to clinical laboratory for risk assessment in obesity and personalized medicine.