Researchers in the US have found that people with two parents affected by Alzheimer’s could show features of the disease in the brain years before any symptoms would show. The research is published online on 12 February in the journal Neurology.
Research has shown that some changes in the brain characteristic of Alzheimer’s disease can occur long before symptoms can be detected in the clinic. Understanding how the brain is affected early in Alzheimer’s could provide clues to the causes of the disease and help to improve the accuracy and timing of diagnosis.
To investigate the factors influencing these early features, researchers in New York studied 52 people without dementia aged between 32 and 72. The volunteers were split into four groups depending on whether their parents had been affected by late-onset Alzheimer’s, the most common form of the disease which affects people over 65. The four groups comprised those with neither parent affected, both parents affected, and either their mother or father having developed the disease.
Volunteers underwent brain scans to look for structural changes in the brain, as well as measuring brain activity and levels of the protein amyloid, a key feature of Alzheimer’s. Amyloid is known to build in the brain at an early stage of Alzheimer’s so may be an indicator that someone may go onto develop the disease.
The researchers found that volunteers whose parents had both been affected had smaller brain volumes, lower levels of metabolism and higher levels of the amyloid protein than those in the other groups. Amyloid levels and brain activity measurements were intermediate for those whose mothers were affected compared to those whose fathers were affected or had no immediate family history of Alzheimer’s.
The findings suggest a proportional relationship between family history and whether people show features in the brain that could be indicative of Alzheimer’s disease. It also suggests these features could be evident in the brain years before symptoms show.
Dr Simon Ridley, Head of Research at Alzheimer’s Research UK, the UK’s leading dementia research charity, said:
“We know that Alzheimer’s can cause changes in the brain many years before symptoms start and this very small study suggests that genetics could be linked to these changes. Research is showing that genes can play a role in the risk of late-onset Alzheimer’s, but it is a complex disease with many risk factors and age is still the biggest. This study only provides a single snap-shot in time, so we do not know how these features have changed over time and, more crucially, whether the volunteers would actually go onto develop Alzheimer’s.
“Characterising the earliest changes in Alzheimer’s and understanding what drives them is a key goal for dementia research. Early detection of Alzheimer’s can help improve diagnosis and ensure that new treatments are tested at a time when they might make the most difference. The best way to study how Alzheimer’s develops is to monitor brain changes over time in large groups of people. While this kind of study is a huge undertaking, Alzheimer’s Research UK is committed to funding such research, to make the progress that is so desperately needed.”