MicroRNA shows promise as Alzheimer's diagnostic test

29 July 2013

New research has suggested a possible new method for diagnosis of Alzheimer’s disease from a blood sample.
Diagnosis of Alzheimer’s is difficult, currently requiring a combination of brain imaging and cognition testing; definitive diagnosis requires post-mortem examination of the brain.
The new research used next-generation sequencing of microRNAs (miRNAs) from blood samples taken from Alzheimer’s patients and healthy controls, identifying a panel of 12 miRNAs differentially expressed in those with Alzheimer’s. Testing on blood samples from a fresh sample of just over 200 people – half of them with Alzheimer’s, and the rest either healthy controls or patients with a range of other neurological and psychiatric conditions, including mild pre-cognitive impairment, which typically precedes any of these disorders.
A signature of 12 miRNAs was found to distinguish between Alzheimer’s and healthy controls with 93% accuracy, and between Alzheimer’s and other diseases with 74-78% accuracy. The researchers propose that Alzheimer’s specific miRNA expression signatures merit further investigation and might ultimately be useful as non-invasive diagnostic tools, in combination with other techniques such as brain imaging.
Comment: This study is a small one and has various other limitations – for example, the researchers note that miRNA expression patterns in blood do not necessarily mirror those of tissue. However, there is an urgent need for better diagnostics for Alzheimer’s, especially to detect the disease in earlier stages when treatments could be much more effective, so these results certainly merit further investigation. 

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