Answer:
Memory loss.
Explanation:
The prominent symptom of Alzheimer's disease is memory loss. The first manifestation of the disease is near memory loss. Patients tend to forget things and their ability to learn is significantly reduced. For example, they may not remember to eat at night the night before. Things may be forgotten as soon as you turn your face, it is a prominent near memory disorder; further development is not good in long-term memory. The stressed memory of the precursors of Alzheimer's disease is not good, mainly because the ability to learn new knowledge is reduced, that is, near memory: what just happened is forgotten. Such as: a box full of balls, throwing balls into this box can not throw in, the ability called learning new things has decreased. In the later period of moderate to severe, long-term memory declines, and what you remember will be lost. So we can judge its precursor from the aspect of memory.
<em>Genetic mutation is an important factor that contributes to the pathogenesis and development of Alzheimer’s disease (AD). The genetic factors studied include the dominant mutations of genes encoding amyloid-β precursor protein (APP), presenilin 1 (PSEN1), and presenilin 2 (PSEN2). Additionally, more and more genes have been found to be potentially associated with AD, such as apolipoprotein E (APOE), glycogen synthase kinase 3 beta (GSK3B), dual specificity tyrosine-phosphorylation-regulated kinase 1A (DYRK1A), and Tau. Although many studies on the treatment of AD have not been successful, gene therapy is still considered as a potential way against AD, and some gene-therapy-based therapeutics have entered the clinical trial stage. Existing strategies for gene therapy against AD include gene inactivation, genetic modification (https://www.creativebiomart.net/alzheimacy/therapeutics/gene-therapy/), and immunoregulation, etc.</em>
