MEF2C and Alzheimer disease: Pathways involved in angiogenesis were enriched in the two-layer neighbourhoods of other GWAS genes that showed altered expression in EC, such as MEF2C, CCN2 and ADAM10. Functionally less well characterised AD GWAS genes, WWOX and IQCK, have large neighbourhoods in the FB and PC co-expression networks associated with enrichment for pathways supporting maintenance of BBB integrity9.