It is interesting to note that while deletion of a region on chromosome 16 that contains SH2B1 increases the risk of obesity significantly (Bochukova et al., 2010; Walters et al., 2010), reciprocal duplication of this region results in an increase in gene dosage which influences BMI in the reverse manner (leanness) (Jacquemont et al., 2011). Here, SH2B1 is linked to obesity disorder.