From the Guidelines
Amyloid Beta and Tau protein are markers for Alzheimer's disease.
Biomarkers for Alzheimer's Disease
The diagnosis of Alzheimer's disease can be supported by the use of biomarkers, which can be divided into several classes, including those that directly reflect the pathology of AD, such as Amyloid Beta (Aβ) and Tau protein 1.
- Amyloid Beta (Aβ): Aβ deposition in plaques is a hallmark of AD, and markers of Aβ deposition, such as cerebrospinal fluid (CSF) measures of lower Aβ42 levels and positron-emission tomography (PET) evidence of Aβ deposition, can be used to support the diagnosis of AD 1.
- Tau protein: Tau accumulation, including CSF measures of increased total tau or phosphorylated-tau (p-tau), is also a key feature of AD, and can be used in combination with Aβ biomarkers to increase the likelihood of progression to AD in patients with mild cognitive impairment (MCI) 1.
Clinical Diagnosis of Alzheimer's Disease
The clinical diagnosis of Alzheimer's disease can be established by the presence of amyloid and tau biomarker positivity, which is required for a diagnosis of AD, as an amnestic phenotype with only amyloid positivity is not specific to AD and can be seen in other neurodegenerative diseases 1.
Cerebrospinal Fluid Biomarkers
Cerebrospinal fluid (CSF) biomarkers, including Aβ42, total tau, and phosphorylated tau (p-tau), can be used to support the diagnosis of AD, and have been shown to have predictive value in patients with MCI 1.
Blood Biomarkers
Blood biomarkers, including plasma phosphorylated tau (p-tau), have also been developed for the diagnosis of AD, and have been shown to accurately separate AD dementia from other neurodegenerative diseases with high diagnostic accuracy 1.
From the Research
Markers for Alzheimer's Disease
The following are considered markers for Alzheimer's disease:
- Amyloid Beta: implicated in the pathogenesis of Alzheimer's disease and considered a main pathological hallmark of the disease 2, 3, 4, 5
- Tau protein: also implicated in the pathogenesis of Alzheimer's disease and considered a main pathological hallmark of the disease 2, 3, 6, 4, 5
- Ubiquitin: involved in the ubiquitination modification processes and related protein ubiquitination degradation pathways in Alzheimer's disease 3, 6, 4
Comparison of Markers
Notch 3 is not mentioned in the provided studies as a marker for Alzheimer's disease. In contrast, Amyloid Beta and Tau protein are consistently mentioned as key players in the disease's pathogenesis. Ubiquitin is also implicated in the disease, particularly in the context of protein homeostasis and degradation.
Diagnostic Markers
Some studies suggest that certain markers, such as CSF total tau (t-tau) and beta-amyloid 1-42 (Abeta(1-42)), may be useful in discriminating early and incipient Alzheimer's disease from other conditions 5. Phosphorylated tau (p-tau) proteins may also improve early and differential diagnosis, as well as disease prediction in subjects at risk for Alzheimer's disease 5.