The expression levels of Bax are significantly increased in the spinal cord of SMA mice, and the overexpression of Bcl-xL increases SMN-reduced MN survival (Garcera et al., 2011) and can extend SMA mice lifespan (Tsai et al., 2006; Tsai et al., 2008). The gene discussed is SMN2; the disease is proximal spinal muscular atrophy.