MAPT and Alzheimer disease: In line with its aberrant release from cortical synapses [73] and its accumulation in peripheral CerebroSpinalFluids (CSF) from AD-affected subjects [52], this soluble N-terminal truncated tau specie(s) turned out to be present in the vitreous body, an ocular fluid whose protein composition depends on secretion from surrounding tissues (ciliary body and retina) [74].