(A) ARSA activity in PBMC (left y axis) and LV content in BM (right y axis) of untreated (Arsa^–/–), mock-treated (GFP), and GT-treated (pool and groups A and B) Arsa^–/– mice and WT controls. ARSA activity is expressed as fold increase compared with WT levels and LV content in CpC. (B) ARSA activity (left y axis) and LV CpC (right y axis) from liver samples from the same groups as in A. (C) ARSA activity of brain extracts is expressed as percentage of WT values. For statistical analysis, see Table 1. (D) Representative TLC gel from Rh-sulfatide test on liver and brain extracts from the indicated mice groups. (E) Assessment of central motor conduction in untreated and mock-treated Arsa^–/– mice, 12-month-old GT mice (pool), and age-matched WT controls (n = 15 mice per group). The GT group showed significantly lower CCT as compared with 6-month-old and age-matched Arsa^–/– mice; comparison with WT mice showed normalization of CCT (*P < 0.05, **P < 0.01). (F) Behavioral evaluations of GT mice. Mean latencies on rotarod ± SEM for each day are indicated. The GT group was indistinguishable from age-matched WT controls (left panel). Twelve-month-old GT mice in group B had a significantly improved performance compared with 6-month-old Arsa^–/– mice, demonstrating correction of the neurological deficit present at the time of treatment (right panel). For statistical analysis, see Table 3 (n = 15–30 mice per group.). GalCer, galactosylceramide.