Indeed, these mismatch cases are not unique to the clinical phenotype caused by TDP‐43 pathology as similar mismatch cases have been identified in other cohorts including Alzheimer's cases with substantial misfolded amyloid and tau deposits, with no concomitant cognitive deficits and the ALS‐PDC cluster on Guam where there were cases with substantial tau neurofibrillary tangles with no associated cognitive deficits 22, 23. This evidence concerns the gene PDC and Cognitive impairment.