RETN and obesity due to melanocortin 4 receptor deficiency: Regarding resistin, visfatin, leptin, and osteopontin, it is important to highlight that when a model excluding anthropometric measures or inflammatory factors was applied (see Additional file 3: Tables S8 and S9), the association of clinical severity with resistin and visfatin persisted, suggesting that their effects were not completely explained by obesity or TNF-α.