Special mention should be given to Growth/differentiation factor 15 (GDF15) a member of the transforming growth factor−β cytokine superfamily that is strongly correlated with chronological aging even in healthy individuals, is a strong risk factor for cardiovascular disease, and strongly predict age-related adverse health outcomes, including obesity, cancer, neurodegenerative diseases, metabolic diseases, cognitive impairment and frailty (Wollert et al., 2017; Cardoso et al., 2018; Tanaka et al., 2018; Lehallier et al., 2019). Here, GDF15 is linked to obesity due to melanocortin 4 receptor deficiency.