LEP and obesity due to melanocortin 4 receptor deficiency: Although the relationship between the HOMA-IR value and BMI is much weaker in children than in adults [39], it has been established that HOMA-IR values are naturally higher in individuals with overweight/obesity than in those with normal-weight [26], largely due to the close association between IR and obesity [26, 36–38], as well as leptin [25].