**Question:** True about Alzheimer's disease - a) Mutation in APP gene, b) Autoantibody, c) Aluminium is a risk factor, d) Viral infection has increased risk, e) Hereditary

**Core Concept:** Alzheimer's disease (AD) is a neurodegenerative disorder characterized by progressive memory loss and cognitive decline. It is a multifactorial condition, involving both genetic and environmental factors. The question presents five options related to Alzheimer's disease, with the aim of determining the true statements among them.

**Why the Correct Answer is Right:**

a) Mutation in APP gene - Alzheimer's disease is linked to mutations in the amyloid precursor protein (APP) gene. Mutations in the APP gene can lead to abnormal production of amyloid-beta peptides, which accumulate in the brain, forming plaques and contributing to the development of Alzheimer's disease.

b) Autoantibody - Autoantibodies are not directly associated with Alzheimer's disease, although autoimmune reactions have been suggested in some studies. However, the correct statement should focus on genetic and environmental factors, rather than autoantibodies.

c) Aluminium is a risk factor - While aluminum has been implicated in Alzheimer's disease, the evidence supporting it as a sole cause is weak. Other factors, such as genetics and lifestyle, play a more significant role in the development of Alzheimer's disease.

d) Viral infection has increased risk - Infectious agents like herpes simplex virus, human immunodeficiency virus (HIV), and Epstein-Barr virus have been associated with increased risk of Alzheimer's disease. However, viral infection itself is not a direct cause of Alzheimer's disease but rather a potential contributor to the development of the disease.

e) Hereditary - Alzheimer's disease has a strong genetic component, with multiple genes involved in the development and progression of the disease. Familial Alzheimer's disease is caused by mutations in genes like APP, PSEN1, and PSEN2, which contribute to the production and clearance of amyloid-beta peptides.

**Why Each Wrong Answer is Incorrect:**

a) Mutation in APP gene - While mutations in the APP gene are a significant contributor to Alzheimer's disease, other genetic factors and environmental factors play a more critical role in the development of the disease.

b) Autoantibody - Autoantibodies are not a direct cause of Alzheimer's disease, but rather a potential byproduct of the disease process.

c) Aluminium is a risk factor - While aluminum exposure may increase the risk of Alzheimer's disease, it is not the primary cause of the disease. The question should focus on genetic and environmental factors rather than the role of aluminum.

d) Viral infection has increased risk - Viral infections can potentially increase the risk of Alzheimer's disease, but they are not the direct cause of the disease. The focus should be on genetic and lifestyle factors.

e) Hereditary - Alzheimer's disease is primarily caused by a combination of genetic factors (e.g., APP, PSEN1, and PSEN2 mutations) and environmental factors, rather than being solely he