SV2A and early-onset autosomal dominant Alzheimer disease: Abbreviations: 95% CI, 95% confidence interval; AD, Alzheimer’s disease; aMCI, amnestic mild cognitive impairment; AUC, area under the curve; Con, control; CSF, cerebrospinal fluid; PDD, Parkinson’s disease dementia; SEN, sensitivity; SPE, specificity; SV2A, synaptic vesicle glycoprotein 2 A; VaD, vascular dementia