Figure 4. Postsymptomatic restoration of SMN enhances survival of SMA model mice.

(A) Restoration of SMN at P4 results in a 23-fold increase in survival of approximately 50% of mutant mice. Control animals were also treated with TM at P4 and are WT for murine Smn on at least 1 allele. χ² (treated versus untreated mutants) = 48.65, P < 0.0001, log-rank test. (B) Adult TM-treated mutants have approximately 60% the weight of WT controls (**P < 0.01) but are phenotypically indistinguishable when tested in (C) grip strength (corrected for body weight), (D) rotarod, and (E) open-field assays. n ≥ 5, P > 0.05 in each case for C–E, Student’s t test. Data are represented as mean ± SEM.