Protein signature may predict Alzheimer’s

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Three biomarkers in spinal fluid may be enough to diagnose Alzheimer’s disease — or to give warning of developing Alzheimer’s pathology before symptoms appear.

In a study of more than 400 older adults, released yesterday by the medical journal Archives of Neurology, a telltale protein signature  was present in 90% of patients already diagnosed with probable Alzheimer’s disease, and in 72% of the cognitively impaired. The signature was also present, however, in just over one third of the cognitively normal patients. But authors of this new study — led by Geert De Meyer at Belgium’s University of Ghent and the Alzheimer’s Disease Neuroimaging Initiative — say that this last finding should not be surprising. Alzheimer’s pathology may be present for many years before a patient develops symptoms, and recent neurological studies show that cognitively healthy people can indeed have plaque build-ups in the brain.

In a second and much smaller study group (57 cognitively impaired patients), De Meyer and colleagues found that their biomarker signature correctly predicted 100% of people who would go on to develop Alzheimer’s disease over five years.

Although Alzheimer’s is one of the most widely feared diseases, diagnosis has been, to date, quite difficult. Patients are most often diagnosed from results of cognitive tests, with clinical confirmation possible only after death, during autopsy. New diagnostic possibilities have emerged in the last few years, however, with improvements in brain-imaging technology.

The diagnostic signature used by De Meyer and his fellow researchers is based on concentrations of three biomarkers in cerebrospinal fluid: beta-amyloid protein 1-42 (CSF Aß1-42), total tau protein and phosphorylated tau181P (P-Tau181P) protein. Cerebrospinal fluid tests could become a routine part of Alzheimer’s screening, according to researchers not affiliated with the research group behind the new study.

There is no cure for Alzheimer’s, but new drugs can slow the disease progression, if it’s caught early.