A blood based 12-miRNA signature of Alzheimer patients
We applied Next-Generation Sequencing (NGS) to miRNAs from blood samples of 48  AD (Alzheimer''s Disease) patients and 22 unaffected controls, yielding a total of 140 unique mature miRNAs with significantly changed expression level. Of these, 82 were higher and 58 lower abundant in samples from AD patients. We selected a panel of 12 miRNAs for a qRT-PCR analysis on a larger cohort of 202 samples including not only AD patients and healthy controls but also patients with other CNS illnesses: Multiple Sclerosis, Parkinson''s Disease, Major Depression, Bipolar Disorder, Schizophrenia, and Mild Cognitive Impairment, which is assumed to represent a transitional period before the development of AD. MiRNA target enrichment analysis of the selected 12 miRNAs indicated an involvement of miRNAs in nervous system development, neuron projection, neuron projection development, and neuron projection morphogenesis, respectively. Using this 12-miRNA signature we were able to differentiate between AD and controls with an accuracy of 93.3%, a specificity of 95.1%, and a sensitivity of 91.5%. The differentiation of AD from other neurological diseases was possible with accuracies between 73.8% and 77.8%. The differentiation of the other CNS disorders from controls yielded even higher accuracies. Overall design: Examination of the miRNA profile in blood samples of 48 AD patients and 22 controls