Since, however, the loss of Gas6, a ligand for both Mer and Axl, also protects mice against HFD-induced obesity [58], and obesity in humans is associated with increased plasma Gas6 levels [59,60], decreasing Gas6 levels by neutralizing antibodies [61] might be a more realistic approach to target obesity. This evidence concerns the gene AXL and obesity due to melanocortin 4 receptor deficiency.