CEBDAD

Criteria to Establish a Biochemical Diagnosis of Alzheimer's disease

Nonoverlapping but synergetic tau and APP pathologies in sporadic Alzheimer's disease.
Neurology. 2002 Aug 13;59(3):398-407.
PMID: 12177374

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Our laboratory is able to analyze brain tissues for a biochemical diagnosis. Contact: A. Delacourte 
Qualitative and quantitative analyses of
- tauopathies
- Abeta; APP-CTFs
- synucleinopaties

It is possible to propose the following criteria to establish a (post-mortem) biochemical diagnosis of Alzheimer’s Disease (CEBDAD): 

- presence of Aß peptide x-42 above 30 micrograms per gram of tissue and simultaneous presence of PHF-Tau in two polymodal association brain areas: Brodmann areas 9 and 39. 

With these criteria, there is no overlap between aging and AD. The diagnosis of infra-clinical AD can also be proposed, taking into account the pathway of NFD. From our data, these criteria are the presence of PHF-Tau in the hippocampal and temporal area (Brodmann area 20 and 21) associated with the presence of amyloid deposits in cortical areas (at the histological or biochemical levels). In the same way, the criteria for the status of non-Alzheimer controls are the following ones: either total absence of PHF-Tau in the brain or presence of PHF-Tau restricted to the hippocampal area for those older than 75 years, and an absence (or very discrete) of amyloid deposits. 

Thus, using such criteria, one can obtain an AD diagnosis close to 100% specificity and sensitivity. These criteria should be useful for the assessment of frozen brain samples from brain banks.

The approach is complementary to the neuropathological one.

This approach could be used for biopsies, and therefore able to give an ante-mortem diagnosis of AD.

 

Delacourte A, David JP, Sergeant N, Buee L, Wattez A, Vermersch P, Ghozali F, Fallet-Bianco C, Pasquier F, Lebert F, Petit H, Di Menza C.

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