The addition of Aβ42 alone (AUROC 0.896, 95% CI: 0.823–0.969, p < 0.001) or all three AD biomarkers (AUROC 0.915, 95% CI: 0.848–0.983, p < 0.001) only marginally affected the diagnostic accuracy of the combined NFL and sAβPPβ (not shown). This evidence concerns the gene NEFL and Alzheimer disease.