Blood DNA methylation signatures to detect dementia prior to overt clinical symptoms

Introduction This study determined whether blood DNA methylation (DNAm) patterns differentiate individuals with presymptomatic dementia compared to controls. Methods DNAm was measured in 73 individuals prior to dementia diagnosis and 87 cognitively healthy controls matched for age, sex, smoking, education, and baseline cognition. DNAm was also measured at 3 years follow-up in 25 dementia cases, and 24 controls. Results Cases and controls differed in DNAm (unadjusted P < .01) at the time of diagnosis (n = 28,787 probes), and pre-diagnosis (n = 15,111 probes), with cg01404610 (General transcription factor IIA subunit 1 gene) significant after correction for multiple testing. Overall, 1150 probes overlapped between analyses (methylation differences from -10.6% to +11.0%), and effect sizes increased from pre-diagnosis to diagnosis. Discussion Discernible blood DNAm signatures are in dementia cases before the appearance of overt clinical symptoms. Blood-based methylation may serve as a potential biomarker of dementia, but further investigation is needed to determine their true clinical utility.