NEGR1 and Onset: Many of these genes are associated with processes in the central nervous system, including synaptic function, intercellular adhesion, and glutamate signaling (CADM2, ELAVL4, GRID1, NRXN3, NEGR1, SCG3), cause monogenic obesity syndromes (BDNF, BBS4, MC4R, POMC), or function in extreme/early onset obesity in humans and mouse models (NEGR1, SH2B1).