FASLG and obesity due to melanocortin 4 receptor deficiency: This parallels previous data from our group which reported significantly lower frequencies of TRAIL+ and FasL+ NK cells in the circulation of obese compared to non-obese OAC patients, a further indication of the often dysfunctional NK cell phenotype seen in patients with obesity, which can manifest as diminished NK cell cytotoxicity17,18,35,36.