In the present study, we used a C. elegans model for Spinal Muscular Atrophy (SMA),in which smn-1, the ortholog of SMN1, has been silenced via RNAi specifically in 19 motoneurons. These animals display an age-dependent degenerationof motoneurons (MNs) detected as altered locomotion, the early disappearanceof neurons expressing the green fluorescent protein, and finally theapoptotic death of targeted neurons. Here, SMN1 is linked to proximal spinal muscular atrophy.