In contrast, NAT availability in the hypothalamus is assumed to decrease from normal-weight (BMI 18.5–25 kg/m2) to moderate obesity (BMI 30–35 kg/m2) and to increase from moderate to severe obesity (BMI  > 35 kg/m2) forming a U-shaped curve [7]. The gene discussed is BRD2; the disease is obesity due to melanocortin 4 receptor deficiency.