Causes of Alzheimer’s disease (AD), one type of dementia, have been attributed to (i) degradation of the neurotransmitter acetylcholine by acetylcholinesterase (AChE) and butyrylcholinesterase (BChE), or (ii) accumulation of amyloid plaque formed during amyloidogenesis by β-secretase (BACE-1) [25]. The gene discussed is BACE1; the disease is early-onset autosomal dominant Alzheimer disease.