Tau-441 is a member of the Tau family of proteins. Tau proteins are mainly expressed in the neurons of the central nervous system where they exert a role in stabilizing microtubules, key components of axonal transport, as well as in signal transduction.Tau proteins are subject to phosphorylation and this phenomenon regulates the association of the Tau protein with the microtubules. Deposits of Alzheimer′s disease AD-associated proteins, such as hyperphosphorylated Tau, as well as other shared misfolded proteins, such as, β-amyloid precursor protein (βAPP), ubiquitin, and various chaperones and protein kinases are thought to play a pathologic role in the cognitive decline and muscular failure.3 Malfunctioning of Tau proteins is associated with microtubules disintegration and collapsing of the neuronal transport system. Among other diseases, Tau forms in cerebrospinal fluid are considered a reliable biomarker for progressive supranuclear palsy, where the levels of Tau forms ratio were significantly reduced.