Genetic inhibition of ASM improves motor behavioral deficits in FUS-R521C mice. (A) Top, the majority of FUS-R521C mice show growth retardation, spastic paraplegia, and severe muscle wasting, but this is not evident in FUS-R521C; Smpd1+/− mice. Bottom, the FUS-R521C mice also exhibit prolonged hind limb clasping on the tail-suspension test, but this is not evident in the FUS-R521C; Smpd1+/− mice. (B, C) Images of hind limb clasping in mice and the quantification of clasping duration on the tail suspension test (n = 4 per group). (D) Holding impulse of each group on the hanging wire test (n = 7-8 per group). (E) Rotarod scores of each group on the rotarod test (n = 7 per group). One-way analysis of variance, Tukey’s post hoc test. *P < 0.05, ***P < 0.001, ****P < 0.0001. All error bars indicate S.E.M. All data analysis was done on 12-week-old mice.