C9orf72 and amyotrophic lateral sclerosis: Statistically significant specificity has, however, only been demonstrated for the basal ganglia’s nucleus accumbens region (Table 1), and only in analyses that excluded the ALS-genetic variants known to contribute to cerebellar pathology in ALS, including C9orf72. This is perhaps somewhat contraintuitive to previous studies, which argued a more intensive basal ganglia involvement in patients with ALS carrying the C9orf72 hexanucleotide repeat expansion8.