C9orf72 and Alzheimer disease: Both molecules have demonstrated encouraging biomarker properties in the framework of FTD: for instance, miR-223–3p, miR-15a-5p, and miR-22–3p microRNA measurements in blood samples may distinguish FTD from AD [161], the relative expression of NORAD and NEAT1 long non-coding RNAs in mononuclear cells is more abundant in C9orf72 carriers, and the relative transcription of GAS5 long non-coding RNAs is less abundant in mononuclear cells in GRN mutation carriers [162]; nevertheless, further research is warranted to establish their exact place in daily practice and research.