One explanation for such a result is that the activity and/or levels of sarcoplasmic reticulum (SR) Ca2+-ATPase (SERCA2a) may be compromised by obesity; however, previous studies realised in our laboratory demonstrated that SERCA2a is not damaged, but the authors found a reduced phospholamban (PLB) phosphorylated at serine16 [36]. This evidence concerns the gene PLN and obesity due to melanocortin 4 receptor deficiency.