Gene knockout studies showing vacuolization and other pathologies of Canavan disease to be absent when both Aspa and Nat8L (Asp-NAT) are ablated provide strong evidence that the buildup of NAA in oligodendrocytes and/or neurons is deleterious (Guo et al., 2015; Maier et al., 2015; Toriumi et al., 2015; Ahmed et al., 2016; Sohn et al., 2017). Here, ASPNAT is linked to Canavan disease.