Appetite (feeling of hunger and feeling of being full after eating) and weight can be controlled by certain genes located in the brain. These genes are part of the Melanocortin-4-Receptor pathway (MC4R). Sometimes there is a genetic change (variation) in one of these genes. You have been identified as potentially having such a variation. This study will include 5 sub-studies. Each sub-study will look at one of the following gene variations in the melanocortin-4 receptor (MC4R) pathway:Sub-study 035a: pro-opiomelanocortin (POMC) or proprotein convertase subtilisin/kexin type 1 (PCSK1); Sub-study 035b: leptin receptor (LEPR); sub-study 035c: steroid receptor coactivator-1 (SRC1); Sub-study 035d: src homology 2B adaptor protein 1 (SH2B1); Sub-study 035e: a certain variation in the PCSK1 gene called PCSK1 N221D. In each sub-study, the study Sponsor wants to find out if an investigational drug called setmelanotide (RM-493) can help control body weight and hunger in people with your condition.