When applied to Cohort 2 for which full clinical data were available, the five 'validated biomarkers' could individually differentiate AD from non-AD healthy control CSF with areas under the curve (AUC) as follows: total apoE=0.62; cystatin C=0.62; MDH=0.67; osteopontin=0.79; and YKL-40=0.75. This evidence concerns the gene SPP1 and Alzheimer disease.