With regard to mitochondrial uncoupling protein 1 (UCP-1), which was previously shown to have a central role in thermogenic response in BAT and whose level was reported to decline in this organ with obesity (Shimizu et al, 2014), it was also shown that its deficiency promoted ER stress in BAT (Bond et al, 2018). Here, SLC25A19 is linked to obesity due to melanocortin 4 receptor deficiency.