The FK506-binding protein 51 (FKBP51) has been identified as a key player in several diseases such as chronic pain, obesity, and like stress-related disorders (Cioffi et al., 2011; Pöhlmann et al., 2018; Häusl et al., 2019). The gene discussed is FKBP4; the disease is obesity due to melanocortin 4 receptor deficiency.