STX6 and supranuclear palsy, progressive, 1: Variants in and near to the syntaxin-6 (STX6) gene are genetic risk factors for sCJD8 and the most common primary tauopathy, progressive supranuclear palsy (PSP).44-48 Syntaxin-6 is a member of the SNARE protein family,10 which mediate the final step of membrane fusion during vesicle transport, and thus its identification in GWAS implicated intracellular trafficking as a causal disease mechanism.