BDNF and early-onset autosomal dominant Alzheimer disease: The primary efficacy outcomes included cognitive function, which was assessed by the Korean mini-mental status examination-2 (K-MMSE-2) and the Alzheimer's disease assessment scale-cognitive subscale (ADAS-Cog), and plasma amyloid β (Aβ) and brain-derived neurotrophic factor (BDNF) levels, which were measured as secondary biochemical markers.