Such an interaction was described by Lu et al. [14] who found that a combination of a polymorphism in the LEP 3′ flanking region with two polymorphisms in LEPR (K109R and K656N) was associated with obesity in a Chinese population, even though none of them individually were associated with body weight or BMI. This evidence concerns the gene LEPR and obesity due to melanocortin 4 receptor deficiency.