White Matter Hyperintensities Precede Alzheimer's Onset

A new study suggests that autosomal dominant Alzheimer's disease (AD) is associated with increased white matter hyperintensities (WMH) on magnetic resonance imaging (MRI), evident well before symptom onset.

 

Researchers at Columbia University (New York, NY, USA), Washington University School of Medicine (WUSTL; St. Louis, MO, USA), and other institution participating in the Dominantly Inherited Alzheimer Network (DIAN; St. Louis, MO, USA), conducted a study involving 299 participants (median age 39 years), including 184 who had a mutation that results in AD, and 115 of their first-degree relatives who served as non-carrier controls.

 

The researchers than calculated the estimated years to AD from expected symptom onset by subtracting the affected parent's symptom onset age from the participant's age. Baseline MRI data were also analyzed for total and regional WMH. The researchers found that mutation carriers had greater total WMH volumes, which increased approximately six years prior to expected symptom onset. The effects were most prominent for the parietal and occipital lobe, which showed divergent effects as early as 22 years prior to estimated onset. The study was published on March 26, 2016, in Annals of Neurology.

 

“Autosomal dominant Alzheimer's disease is associated with increased WMH well before expected symptom onset,” concluded lead author Seonjoo Lee, PhD, of Columbia University, and colleagues. “The findings suggest the possibility that WMH are a core feature of Alzheimer's disease, a potential therapeutic target, and a factor that should be integrated into pathogenic models of the disease.”

 

The white matter of the brain contains the neuronal fibers that transmit information around the living brain. Historically, the vast majority of neuroscience research effort has been invested in understanding and studying gray matter and neurons, while white matter has received relatively little attention, largely due to the lack of effective research tools to study it, even though it comprises about half the volume of the brain.

 

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