Elevated blood levels of soluble Axl have recently been reported to mark a variety of human disease and trauma states, including aortic aneurysm (Ekman et al., 2010b), lupus flares (Zhu et al., 2014), pneumonia infection (Ko et al., 2014), preeclampsia (Liu et al., 2014), coronary bypass (Lee et al., 2013), obesity and insulin resistance (Hsiao et al., 2013), and limb ischemia (Ekman et al., 2010a). The gene discussed is AXL; the disease is obesity due to melanocortin 4 receptor deficiency.