Other adipokines, such as PRGN (also known as granulin/epithelin precursor), nesfatin-1 (nesfatin), visfatin/PBEF/NAMPT, apelin, RBP-4, and PAI-1 have been described as signal molecules involved in obesity and metabolic syndrome. This evidence concerns the gene NUCB2 and obesity due to melanocortin 4 receptor deficiency.