Biomarkers in non-Alzheimer dementias

Biomarkers for Alzheimer's Disease (AD) and non-AD dementias could serve as aids to diagnosis and treatment. Biochemical markers have been sought in cerebrospinal fluid (CSF), blood and urine, and are best developed for AD. Ideally, a biomarker should be unique to a dementing disorder and should have high sensitivity. The most widely studied markers for AD, CSF tau and Aβ42, also can show alterations in other disorders. Some non-AD dementias, such as Lewy Body dementia and vascular dementia may be accompanied by AD pathology, making the search for unique markers of these common disorders difficult. However, markers of general pathological processes in neurodegeneration could be used to follow change over time. Prion disorders come closest to having unique biomarkers, although it is difficult to detect the pathogenic Prion proteins (PrPsc) in body fluids. Other protein signatures, such as increased CSF levels of 14-3-3 protein and markedly increased tau have sufficiently high sensitivity and specificity to be used as aids to diagnosis. The development of markers for prion disease stands as a model to drive future research in other dementias.