There is an evolving appreciation of a common brain disease with TAR-DNA binding protein 43 (TDP-43) proteinopathy that mimics Alzheimer’s disease (AD) clinically [5, 25, 26, 34, 39, 50] and affects 10–25% of persons aged 85 or older [5, 19, 21, 33, 50]. This evidence concerns the gene TARDBP and early-onset autosomal dominant Alzheimer disease.