After performing pairwise comparisons, patients with aMCI due to AD had significantly higher Ng concentrations than patients with MCI due to FTLD (F[1, 134] = 15.16, p < .001, η2 = 0.08, AUC = 0.66, 95% CI: 0.62–0.84, with a sensitivity of 0.68 and specificity of 0.72) and those with AD dementia had significantly higher Ng concentrations than those with FTLD dementia (F[1, 96] = 4.60, p = .029, η2 = 0.06, AUC = 0.64, 95% CI: 0.49–0.77, with a sensitivity of 0.73 and specificity of 0.52). Here, NRGN is linked to dementia.