C9orf72 and amyotrophic lateral sclerosis: Comparing two genetic subtypes of ALS (i.e., C9orf72-ALS and SOD1-ALS) and their respective matched cohorts of sporadic ALS patients (i.e., C9orf72-matchedsALS and SOD1-matchedsALS) readily revealed more pronounced hypometabolism in the peri-rolandic region, extending to the precuneus, and thalamus, as well as hypermetabolism in the brainstem (i.e., medulla, extending to the pons), in C9orf72-ALS, when compared to C9orf72-matchedsALS.