GPR151 and type 2 diabetes mellitus: In mice, whole-body knockout (KO) of Gpr151 results in diminished behavioral responses to nicotine, including less pronounced suppression of appetite11, The nonsynonymous GPR151 p.Arg95Ter variant is linked to 12% lower odds of clinical obesity6 and a 14% decrease in the odds of T2D6,7, which suggests the presence of a habenula-mediated regulation of appetite or other mechanisms which mediate the effect of GPR151 LOF variants on decreased odds of T2D.