Expression of PICALM was reduced in subjects who underwent gastric bypass surgery to reverse their pro‐inflammatory state of obesity (Ghanim et al., 2012), and PICALM overexpression in vitro was found to reduce the endosomal localization of the mannose‐6‐phosphate receptor (M6PR) which binds to the herpes virus (Brunetti, Dingwell, Wale, Graham, & Johnson, 1998). Here, M6PR is linked to obesity due to melanocortin 4 receptor deficiency.