TMEM18 and obesity due to melanocortin 4 receptor deficiency: In addition, Orkunoglu-Suer et al. [20] found that the same three SNPs that associated with physical activity volume in our study [i.e., MC4R (rs17782313) T>C, TMEM18 (rs6548238) C>T, and SH2B1 (rs7498665) A>G] also associated with body composition phenotypes including BMI among the FAMuSS cohort further substantiating the concept of pleiotropy and our hypothesis of the essential role that physical activity has in mediating overweight and obesity.