TARDBP and amyotrophic lateral sclerosis: In contrast, granules formed by ALS-linked mutant TDP-43 are more viscous and show disrupted axonal transport dynamics, suggesting that the increased viscosity observed in TDP-43 mutant granules may lead to a toxic gain of function, possibly enhancing its propensity for aggregation (Alami et al., 2014; Gopal et al., 2017).