A related example involves two loci associated with BMI, located 5 Mb apart on chromosome 20, both of which colocalize with serum levels of the Agouti signaling protein (ASIP) (Supplementary Fig. 16), known to promote obesity via the melanocortin receptor (MC4R)31. The gene discussed is MC4R; the disease is obesity due to melanocortin 4 receptor deficiency.