ADRB3 and obesity due to melanocortin 4 receptor deficiency: Among genes with positive associations of variants with obesity or obesity-related phenotypes, there are some deeply involved in the regulation of mitochondrial activity and biogenesis in adipose tissues, like ADRB3 (adrenergic, β3 receptor), INS (insulin), PLIN (perilipin), PPARγ (peroxisome proliferative activated receptor, gamma), or UCP1-UCP13 (uncoupling proteins 1–3) [104].