Early onset, earlier detection

A blood test for the diagnosis of early-onset Alzheimer’s disease has been developed.

The test, made by University of Melbourne researchers, has the potential to predict with 91 per cent accuracy that someone will develop Alzheimer’s.

Brain imaging can detect changes that occur two decades before signs of dementia show. The test could predict these changes and a person’s risk of developing Alzheimer’s earlier than now possible.

About 20 per cent of healthy participants with no memory complaints tested positive in an initial trial group of the blood test. The research team said the test must undergo further trials in a larger population across three to five years, as Alzheimer’s is a progressive disease.

Dr Lesley Cheng, from the department of biochemistry and molecular biology Bio21 Institute, said the research is critical for the development of therapeutic and preventative drugs for Alzheimer’s disease. “We can use it to identify patients of high risk and recruit them into clinical trials, and also monitor their improvement upon treatment,” she said.

The method involves harvesting protective bubbles of genetic material called MicroRNA. “What we can do is capture them from the blood stream and what we have done is profile them using

next-generation sequencing,” Cheng said. “We found that 16 of these microRNA are different [when] compared with healthy people.”

The team also plans to develop a test for Parkinson’s disease.

Cheng said the test is similar to a cholesterol or normal health check. She added it also saves on costs with its high-throughput.

“It is just using blood – that is no different to the current diagnostic tests available these days,” she said. “It is a lot cheaper than brain imaging, for example. With brain imaging you have to inject a radioisotope tracer into the patient and obviously it uses expensive PET imaging instruments,” she said.

Cheng said the research team has already had a lot of interest from patients who want to find out whether they are at risk of developing Alzheimer’s disease.

“The blood test would be a great tool as a pre-screen and we can determine which patients should be referred to more expensive testing such as the PET imaging,” she said.

For an individual with a family history of Alzheimer’s disease or who is concerned with their memory, the test could ease concerns, Cheng added. Alternatively, doctors can monitor those who are identified as high risk.

“Almost 70 per cent of those who do suffer from dementia have Alzheimer’s disease – so it is important to identify this group of people so we can tackle it within the research community,” Cheng said.

Lead researcher professor Andrew Hill, also from the Bio21 Institute, said the blood test would advance efforts to find new treatments for Alzheimer’s disease and could lead to better preventative measures.

“This blood test would be crucial to the development of therapeutic and preventative drugs for [Alzheimer’s disease]. It can be used to identify patients for clinical drugs and for monitoring improvement on treatment,” Hill said.