AZGP1 and obesity due to melanocortin 4 receptor deficiency: To explore the relationship between AZGP1 and obesity in humans, circulating AZGP1 levels were measured in overweight (BMI 24–27.9 kg/m2), obese (BMI ≥ 28 kg/m2) and normal-weight (BMI 18.5–23.9 kg/m2) individuals.