Background:
The etiology of Alzheimer’s disease remains poorly understood at the mechanistic
level, and genome-wide network-based genetics have the potential to provide new insights into the
disease mechanisms.
Objective:
The study aimed to explore the collective effects of multiple genetic association signals on an
AV-45 PET measure, which is a well-known Alzheimer’s disease biomarker, by employing a networ kassisted
strategy.
Method:
First, we took advantage of a dense module search algorithm to identify modules enriched by
genetic association signals in a protein-protein interaction network. Next, we performed statistical evaluation
to the modules identified by dense module search, including a normalization process to adjust the
topological bias in the network, a replication test to ensure the modules were not found randomly , and a
permutation test to evaluate unbiased associations between the modules and amyloid imaging phenotype.
Finally, topological analysis, module similarity tests and functional enrichment analysis were performed
for the identified modules.
Results:
We identified 24 consensus modules enriched by robust genetic signals in a genome-wide association
analysis. The results not only validated several previously reported AD genes (APOE, APP,
TOMM40, DDAH1, PARK2, ATP5C1, PVRL2, ELAVL1, ACTN1 and NRF1), but also nominated a few
novel genes (ABL1, ABLIM2) that have not been studied in Alzheimer’s disease but have shown associations
with other neurodegenerative diseases.
Conclusion:
The identified genes, consensus modules and enriched pathways may provide important
clues to future research on the neurobiology of Alzheimer’s disease and suggest potential therapeutic
targets.