Moreover, G279 locates in the truncated part of SMNΔ7 compared with FL-SMN, and two SMA-linked missense mutations (G279C and G279V) were also identified for this glycine [3, 42], highlighting the functional significance of Gly279 (and also the truncated C-terminal part) of FL-SMN. Here, SMN2 is linked to proximal spinal muscular atrophy.