This study uses a new approach to discover biological pathways associated with AD dementia by measuring hundreds of circulatory proteins involved in cellular communication. Combined with multiple levels of statistical and bioinformatics analyses and leveraging current pathway knowledge, we were able to build networks of proteins deregulated in AD. We provide evidence that this approach has considerable robustness for the discovery of proteins and pathways linked to AD and successfully validate it against existing datasets. We show that genomic and transcriptomic data can be used to corroborate suspected disease-specific pathways and identify GDF3 as a new regulator of adult neurogenesis. Given the important function adult hippocampal neurogenesis has in rodent behavior related to memory and learning, the recent discovery of significant hippocampal neurogenesis in the adult human brain even with advanced age [37], and previous implications of disturbed neurogenesis in AD [38, 39], changes in neurogenesis caused by abnormal GDF3 signaling might well have a role in the development or progression of AD.