Although the expression of SLC35D3 in the Allen Brain Atlas (http://www.brain-map.org/) shows a wider distribution, in either WT or mutant mice, we did not detect the SLC35D3 protein in other brain sub-regions and especially in the obesity-related brain tissues such as thalamus and hypothalamus (Fig. 3A), as well as in several organs involved in energy homeostasis such as adipose tissue, pancreas, liver and skeletal muscle (Fig. 3B). This evidence concerns the gene SLC35D3 and obesity due to melanocortin 4 receptor deficiency.