Accumulating evidence has indicated that STEAP4 is a novel anti-obesity gene that is regulated by multiple factors, including nutritional stress, hormones, pro-inflammatory factors, and adipokines (Chen et al., 2010; Fasshauer et al., 2003; Kralisch et al., 2009; Moldes et al., 2001; Ramadoss et al., 2010). Here, STEAP4 is linked to obesity due to melanocortin 4 receptor deficiency.