Inflammatory cytokines such as interleukin 6, often associated with obesity, have been shown to down-regulate activity of cytochrome P450 (CYP) enzymes and hepatic drug transporters in mice and humans (Richardson and Morgan, 2005; Schmitt et al., 2011; Cayot et al., 2014; Morgan et al., 2018; Abualsunun et al., 2020). The gene discussed is PPIG; the disease is obesity due to melanocortin 4 receptor deficiency.