SMN2 and proximal spinal muscular atrophy: Again, the p62 protein level was found to be upregulated in the spinal cord of Burghes severe SMA mice compared to their control littermates [171], as well as in an NSC-34 cell line following lentiviral SMN knockdown, and in the spinal cord of Taiwanese SMA mice [166], indicating a reduction in autophagic flux.