FTO and obesity due to melanocortin 4 receptor deficiency: After adjustments for age and gender, and considering only extreme BMI values (i.e. < 25 and >30), only FTO polymorphisms were associated with obesity risk (rs3751812: OR = 1.51, CI [1.14–1.99], P = 0.003, power = 72%; rs850136: OR = 1.52, CI [1.15–2.01], P = 0.003, power = 74%; rs9939609: OR = 1.44, CI [1.09–1.92], P = 0.01, power = 60%).