We found no evidence that baseline cognitive impairment was a predictor of subsequent cognitive decline or that cognitive trajectories differed based on the presence of TMEM106B rs3173615 or UNC13A rs12608932 genetic modifiers, among C9ORF72 expansion carriers or non-carriers (see online supplemental eTable 4 for SNP frequencies, other data not shown). Here, UNC13A is linked to Mental deterioration.