BDNF and obesity due to melanocortin 4 receptor deficiency: The genes and/or miRNAs selected by the five cross-sectional studies detected in our review, were related to obesity (FAIM2) (42), cardiac hypertrophy, angiogenesis and inflammation (miRNA-222 and miRNA-146a) (33, 43, 44), signaling molecule in the immune system (IL-2) (29), brain health (BDNF) (29), T regulatory cells differentiation and function (FOXP3) (45), and stress/cortisol metabolism (HSD11B2) (46).