Depositions of
proteins in form of
amyloid and non-
amyloid plaques are common pathogenic signs of more than 20 degenerative diseases affecting the central nervous system or a variety of peripheral tissues. Among the neuropathological conditions, Alzheimer's, Parkinson's and the
prion diseases, such as
Creutzfeldt-Jakob disease (CJD), present ambiguities as regarding their differential diagnosis. At present, their diagnosis must be confirmed by post-mortem examination of the brain. Currently the ante-mortem diagnosis is still based on the integration of multiple data (clinical, paraclinical and
biological analyses) because no unique marker exists for such diseases. The detection of specific
biomarkers would be useful to develop a differential diagnostic, distinguishing not only different
neurodegenerative diseases but also the disease from the non-pathological effects of aging. Several neurodegenerative
biomarkers are present at very low levels during the early stages of the disease development and their ultra-low detection is needed for early diagnosis, which should permit more effective therapeutic interventions, before the disease concerned can progress to a stage where considerable damage to the brain has already occurred. In the case of
prion diseases, there are concerns regarding not only patient care, but the wider community too, with regard to the risk of transmission of
prions, especially during
blood transfusion, for which, four cases of variant CJD
infection associated with transfusion of non-leukocyte-depleted blood components have been confirmed. Therefore the development of techniques with high sensitivity and specificity represent the major challenge in the field of the
protein misfolding diseases. In this paper we review the current analytical and/or biochemical diagnostic technologies used mainly in
prion, but also in Alzheimer and Parkinson diseases and emphasizing work on the
protein detection as a surrogates and specific
biomarker in the body fluid of patients (urine, CSF and blood). This review highlights the urgency of the development of early and sensitive diagnostics in terms of therapeutic challenge.