GDF15 and obesity due to melanocortin 4 receptor deficiency: This cytokine (named also as MIC-1, PLAB, NAG1, or PTGFB) was recently investigated for obesity treatment and authors suggested to consider GDF-15 a member of Glial Cell-Derived Neurotrophic Factor (GDNF) family due to the high affinity with GDNF family receptor α-like (GFRAL) and its co-receptor Ret proto-oncogene (RET) [9].