**Core Concept**
Henoch-Schonlein purpura (HSP) is a form of vasculitis that primarily affects the small blood vessels, characterized by the deposition of IgA immune complexes. It is a systemic disease that can affect multiple organ systems, including the skin, joints, gastrointestinal tract, and kidneys.

**Why the Correct Answer is Right**
HSP is typically characterized by a tetrad of symptoms: non-thrombocytopenic purpura, arthritis or arthralgia, abdominal pain, and renal involvement. The deposition of IgA immune complexes in the affected tissues leads to inflammation and damage. The presence of these symptoms helps to distinguish HSP from other forms of vasculitis.

**Why Each Wrong Option is Incorrect**
**Option A:** HSP is actually associated with the deposition of IgA immune complexes, not IgG or IgM.
**Option B:** Renal involvement, including hematuria and proteinuria, is a common feature of HSP.
**Option C:** Gastrointestinal symptoms, including abdominal pain and gastrointestinal bleeding, are also characteristic of HSP.

**Clinical Pearl / High-Yield Fact**
It's essential to note that HSP is a classic example of a systemic vasculitis, and its diagnosis is often clinical, with laboratory tests supporting the diagnosis. A high index of suspicion is required, especially in children, as HSP can be a cause of acute kidney injury.

**Correct Answer:** A.