We will summarize recent advances in our understanding of the role of dysregulated IFN signaling in AD, primary tauopathy, TAR DNA-binding protein 43 (TDP-43) proteinopathy including cases associated with C9orf72 hexanucleotide repeat expansion (HRE), and Parkinson’s disease (PD). This evidence concerns the gene C9orf72 and Parkinson disease.