SNAP25 and early-onset autosomal dominant Alzheimer disease: Furthermore, in a study of the ADNI cohort, comprising cognitively normal, mild cognitive impairment, and Alzheimer’s disease patients who were further defined by amyloid-β status, reference point CSF SNAP-25 levels were higher in Alzheimer’s disease patients and those with mild cognitive impairment who were amyloid-β-positive than cognitively normal individuals (amyloid-β-positive or -negative [190].