For targeted studies we measured proteins previously associated with AD or neurodegeneration; in CSF assaying, neurofilament light chain (NFL), monocyte chemotactic protein-1 (MCP-1) and YKL-40 also known as chitinase-3-like-1 [17]; and in plasma, ficolin-2 (FCN2), fibrinogen gamma chain (FGG), complement factor H-related 1 (CFHR1) and apolipoprotein A-I (ApoA1) [18–20] (Baird et al., unpublished observations). This evidence concerns the gene FGG and Alzheimer disease.