FTO and obesity due to melanocortin 4 receptor deficiency: The association between risk-variants of the FTO gene and obesity seems not to be mediated by peripheral factors such as a dysfunctional metabolism (Cecil et al., 2008; Speakman et al., 2008), but rather by increased dietary intake and unhealthy eating behaviors (Brunkwall et al., 2013), probably linked to an aberrant functioning of the reward network (Hess et al., 2013; Sevgi et al., 2015).