COL21A1 and Alzheimer disease: We found eight collagen genes regulated in the MCS formation (COL2A1, COL3A1, COL4A5, COL8A1, COL12A1, COL21A1 in the AD to MCSs comparison; COL2A1, COL4A5, COL8A1, COL12A1, COL21A1, COL6A3 and COL9A2 in the 1g to MCSs comparison, Figure 4) which led together with the regulated matrix metalloproteases to the Gene Ontology GO:0062023 (collagen-containing extracellular matrix) annotation.