Moreover, we evaluated the effects of IRX3 variants on human obesity in a two-stage case-control study including 227 young obese subjects (BMI, 35.1–61.7 kg/m2) and 219 lean controls (BMI, 17.5–23.0 kg/m2) in the first stage; and 634 young obese subjects (BMI, 30.0–63.3 kg/m2) and 697 lean control subjects (BMI, 17.5–23.0 kg/m2) in the second stage (Table 1). Here, IRX3 is linked to obesity due to melanocortin 4 receptor deficiency.