All are true about Autoimmune disease except ?
**Core Concept**
Autoimmune diseases occur when the body's immune system mistakenly attacks and damages its own cells, tissues, and organs. This is due to a loss of tolerance to self-antigens, leading to an immune response against the body's own components. Autoimmune diseases can affect various systems, including the skin, joints, and endocrine system.
**Why the Correct Answer is Right**
Autoimmune diseases often result from a combination of genetic predisposition and environmental factors. The immune system's failure to distinguish between self and non-self antigens leads to the production of autoantibodies and activation of autoreactive T cells. This process can be triggered by various mechanisms, including molecular mimicry, where a pathogen's antigen resembles a self-antigen. Examples of autoimmune diseases include rheumatoid arthritis, lupus, and Hashimoto's thyroiditis.
**Why Each Wrong Option is Incorrect**
**Option A:** This statement is incorrect because autoimmune diseases are not solely caused by a single genetic mutation. Instead, they often involve multiple genetic and environmental factors that contribute to the loss of immune tolerance.
**Option B:** This statement is incorrect because autoimmune diseases can affect various systems and organs, not just the skin. Examples include autoimmune thyroiditis, autoimmune hepatitis, and autoimmune hemolytic anemia.
**Option C:** This statement is incorrect because the immune system's response in autoimmune diseases is not limited to T cells. Both T cells and B cells can be involved in the autoimmune response, leading to the production of autoantibodies and activation of autoreactive T cells.
**Clinical Pearl / High-Yield Fact**
Autoimmune diseases often exhibit a complex interplay between genetic and environmental factors, making it challenging to predict and prevent their development. Understanding the underlying mechanisms and risk factors is crucial for the diagnosis and management of these conditions.
**Correct Answer: A**