VNN2 and obesity due to melanocortin 4 receptor deficiency: The main findings of this study were as follows: (1) there was an increase in serum Vanin-2 concentrations in individuals with obesity and insulin resistance; (2) circulating Vanin-2 concentrations showed associations with IL-18, BMI, FAT%, and HOMA-IR; (3) weight loss following reduced weight surgery was linked to preoperative circulating Vanin-2 levels (Figure 8).