Blood test to predict genetic Alzheimer’s progression

The Dominantly Inherited Alzheimer’s Network (DIAN) study, recently published in Nature Medicine, provides hope that a test could become part of routine medical check-ups, which would provide a cheap and efficient early warning system for genetic Alzheimer’s disease in the community.

The Australian arm of the study was a joint project between Melbourne’s Florey Institute of Neuroscience and Mental Health, University of Melbourne, Western Australian’s Edith Cowan University and Neuroscience Research Australia.

“The blood test accurately predicted when members of a family with inherited Alzheimer’s disease would begin to show symptoms,” Professor Colin Masters from the Florey Institute says.

“Inherited Alzheimer’s is a rare genetic disease. Using this very defined patient population we were able to identify affected family members over a decade before they began to show cognitive impairments.”

Researchers detected raised levels of a protein called neurofilament light (NfL) chain in participants’ bloodstream, which is created when the structure of previously healthy nerve cells is damaged or destroyed.

The study suggests that raised levels of NfLs could be detected as early as 16 years before symptoms start to show in those with this genetic form of the disease.

“NfL levels rise whenever the brain is damaged, and as Alzheimer’s disease affects 30 percent of people over the age of 80, we hope that NfL will become part of a GP’s standard battery, like annual cholesterol testing,” Professor Masters says.

“We would send patients off for more specific Alzheimer’s tests if the results come back showing a cause for concern.”

However, further testing still needs to be done to determine whether these changes would be seen in the people who develop the more common older-onset, or ‘sporadic’, Alzheimer’s disease.

Researchers say that if a patient is identified as being in the early phase of the disease, they could be referred to a pharmacological clinical trial, encouraged to make diet and lifestyle modifications and be placed on existing medications in the hope of slowing down disease progression.