Thus, our findings on ApoD upregulation in the CSF of treated SMA type 3 patients might indicate an initial nusinersen-induced restoration of disrupted lipid metabolism in SMA, which, if prolonged, might lead to the rescue of neuronal processes including neurite outgrowth, neuronal survival and plasticity and, ultimately, to clinical improvement. Here, APOD is linked to proximal spinal muscular atrophy.