In rodents, studies on Spinal Muscular Atrophy (SMA) led to the identification of CTRP3 (C1QTNF3, C1q/Tumor Necrosis Factor-related protein 3), which is secreted by muscle and promotes protein synthesis locally in motor neurons, via the activation of mTOR (Figure 4A). This evidence concerns the gene C1QTNF3 and proximal spinal muscular atrophy.