APP and early-onset autosomal dominant Alzheimer disease: A study mentioned that overexpression of APP showed positive effects on cell health and growth.(27) In fact, APP is essential for neurone generation, neurone plasticity, and neuroprotection.(28) Transgenic mouse models study reported that lower APP is associated with poor cognitive performance, underlying the APP role in cognitive functions.(29) Contrasting, it is widely accepted that excessive APP is known to be able to cause Alzheimer’s disease.