Translating these immunohistochemical observations to clinical assays may prove difficult, as levels of tau in CSF are near the lower limits of biologic detection (Hampel et al., 2010) limiting the further identification of a specific subset of tau in the form of a neoepitope; although one group has found promising evidence for diagnostic utility of specific C-truncated isoforms of tau in PSP through immunoprecipitation and western blotting techniques (Borroni et al., 2008, 2009) and others have developed assays to measure 3- and 4R tau in CSF (Luk et al., 2012). The gene discussed is MAPT; the disease is supranuclear palsy, progressive, 1.