Abstract: The present invention provides a method for diagnosing or assessing a neurodegenerative disease in a test subject, comprising: (i) providing a protein-containing sample that has been obtained from the test subject; (ii) determining the concentration, amount or degree of expression of at least one specific protein isoform and/or glycoform derived from a protein biomarker selected from the group consisting of: clusterin precursor; apolipoprotein A-IV precursor; apolipoprotein C-III precursor; transthyretin; galectin 7; complement C4 precursor; alpha-2-macroglobulin precursor; Ig alpha-1 chain C; histone 2B; Ig lambda chain C region; fibrinogen gamma chain precursor; complement factor H; inter-alpha-trypsin heavy chain H4 precursor; complement C3 precursor; gamma or beta actin; haptoglobin precursor; and the serum albumin precursor, or a fragment thereof; (iii) comparing said concentration, amount or degree determined in (ii) with a reference from a control subject with a specific neurodegenerative disease, deme