FTO and obesity due to melanocortin 4 receptor deficiency: The FTO gene function is unknown but based on its predicted structure, the FTO gene encodes for a non-haeme (FeII) dioxygenase with a potential role in adaptation to hypoxia, lipolysis or DNA methylation.17,18 The FTO protein is expressed in almost all tissues; at the cellular level it has a nuclear localisation.17 The molecular mechanisms involved in the pathogenesis of obesity as well as the role of FTO gene in other complex disorders are unknown.