Editors' note: The underacknowledged PPA-ALS: A unique clinicopathologic subtype with strong heritability

As many as 10%–15% of patients with frontotemporal dementia (FTD) are known to have concomitant amyotrophic lateral sclerosis (ALS), and this association is mainly with the behavioral variant of FTD. However, some patients with primary progressive aphasia (PPA) have also developed ALS. In their observational cohort of 130 patients with semantic variant (n = 64) or nonfluent variant (n = 66) PPA, Tan and colleagues sought to better characterize...