Because of the well known clinical heterogeneity for some tauopathies, that can span e.g. from Amyotrophic Lateral Sclerosis to the very different and neurologically/phenotypically clearly separated FTD also in the same families for mutations/repeat expansions in the gene C9orf72, and e.g. PSEN2, mutations, we do not recommend single-gene diagnostics for the diseases discussed here. The gene discussed is C9orf72; the disease is tauopathy.