Research led by the Centre for Healthy Brain Ageing (CHeBA) has identified genetic patterns associated with white matter hyperintensities (WMH), or signal changes in the brain’s white matter, which are markers of small vessel disease in the brain.
The study which analysed T2-weighted magnetic resonance imaging scans for 320 twin participants in CHeBA’s Older Australian Twins Study is featured in this month’s issue of the eminent journal, Stroke.
Lead author of the study and Co-Director of CHeBA, Professor Perminder Sachdev said the findings were exciting and significant because it was the first time WMH heritability, or the degree to which traits are passed from parent to offspring, was examined for specific cerebral regions and in both sexes.
“We found a strong genetic influence for WMH, but the extent varied across different brain regions. Heritability was higher for deep regions of the brain, but lower for the cerebellum and brain stem,” said Professor Sachdev.
Heritability of deep WMH decreased with age, especially after 75 years, which Professor Sachdev said was consistent with current knowledge.
“We know that there are multiple factors which cause WMH, including several non-genetic factors. It is not surprising that the genetic contribution is less in older participants, since genetic influences on complex traits are dynamic through the life course,” explained Professor Sachdev.
The study also examined differences between men and women, finding higher WMH heritability for all brain regions in women.
These findings informed a new CHeBA research project investigating the genetic determinants of small vessel disease in the brain, best identified by the presence of WMH, generously funded by the John Holden Family Foundation.
“The John Holden Family Foundation is pleased to support innovative research into an under-researched area associated with cognitive decline,” said Mr John Holden.
According to Professor Sachdev, the significance of brain lesions is still controversial, although they have been consistently associated with negative health outcomes including cognitive decline, dementia, neuropsychiatric disorders and motor deficits.
“In our new project, we will bring together a large number of studies from around the world to collectively examine the genetic basis of WMH and lacunes, or silent strokes, and their clinical significance, particularly for dementia and cognitive decline, but also for apathy and falls,” he said.