FTO and obesity due to melanocortin 4 receptor deficiency: The FTO gene encodes for an alpha-ketoglutarate-dependent dioxygenase (Gerken et al., 2007), playing a role in growth and development (Boissel et al., 2009; Daoud et al., 2016), and has been reliably associated with the related conditions of type 2 diabetes, BMI, adiposity and other obesity-related traits (Scott et al., 2007; Zeggini et al., 2007; Lindgren et al., 2009; Thorleifsson et al., 2009; Fox et al., 2012; DIAGRAM Consortium et al., 2014; Wood et al., 2016).