FTO and obesity due to melanocortin 4 receptor deficiency: Hotta et al. [14] reported that the FTO rs9939609 variant is associated with severe obesity in the Japanese (n = 2454, p = 2 × 10-5), and a study from Singapore (n = 2919) also reported significant associations of rs9939609 with BMI and obesity (p < 0.0001) [15].