New biomarker helps differentiate Alzheimer’s from primary 4-repeat tauopathies

A new biomarker makes it easier to distinguish between Alzheimer’s disease and primary tauopathy.

Patients regularly appear in university hospitals with diseases so rare and specific that doctors in private practice are hardly known. Primary 4-repeat tauopathies are a good example. These are diseases mainly related to movement disorders, but with symptoms that can often resemble those of Alzheimer’s disease, making accurate diagnosis difficult. Now, researchers at LMU University Hospital have found biomarkers that allow doctors to reliably distinguish the two conditions – albeit only with data from a particular imaging technique called positron emission tomography (PET).

The new diagnostic algorithm we have developed allows physicians to distinguish between Alzheimer’s disease and primary tauopathies with greater precision, enabling earlier and more accurate diagnosis and supporting personalized treatment strategies.”

Professor Matthias Brendel, principal investigator, acting director of the Department of Nuclear Medicine and member of the SyNergy Cluster of Excellence

The results have now been published in the Journal of the Alzheimer’s Association, Alzheimer’s and dementia.

In Alzheimer’s disease and primary 4-repeat tauopathies, large pathological aggregates of the tau protein are found in the brain. For decades, it has been possible to detect tau proteins for Alzheimer’s disease by analyzing the patient’s cerebrospinal fluid.

Recently, however, researchers have developed radioactively labeled substances (tracers) that, after injection into the body, accumulate in the tau aggregates, which are visible on the PET images. “Our new study shows that tau can be identified with the new tau PET tracer, even in 4-repeat tauopathies – but not in the cerebrospinal fluid, but in very specific parts of the brain known as the subcortical brain areas “explains Roxane Dilcher. lead author of the study.

However, the PET signal is only one part of a complex new diagnostic process. The researchers have also found new biomarkers that indicate the presence of a tauopathy with four repeats. “The diagnosis only becomes truly effective if we analyze a combination of cerebrospinal fluid tests, innovative biomarkers and PET signals in the subcortical areas,” says Matthias Brendel. “Then we can recognize a tauopathy with four repeats with a high degree of certainty.”

“Primary 4-repeat tauopathies are currently diagnosed almost exclusively using clinical criteria – without specific biomarkers that allow a conclusive diagnosis in patients,” says co-senior author Dr. Nicolai Franzmeier, who is also a member of SyNergy. “Establishing a biological definition and associated biomarker workflows will definitely advance the field.”