**Core Concept**
Focal segmental glomerulosclerosis (FSGS) is a disease characterized by the scarring of glomeruli, specifically affecting a segment of a glomerulus in a focal manner. This condition is often associated with podocyte injury and dysfunction.

**Why the Correct Answer is Right**
FSGS typically presents with the collapse of glomerular capillaries due to the loss of podocytes, leading to the obliteration of the capillary lumen and the progression of glomerular scarring. The disease is often associated with the activation of the renin-angiotensin-aldosterone system (RAAS), which contributes to the progression of kidney damage. The pathophysiology of FSGS involves the interaction of various factors, including genetic predisposition, environmental factors, and immune system dysregulation.

**Why Each Wrong Option is Incorrect**
* **Option A:** This option is incorrect because FSGS is not primarily characterized by the proliferation of mesangial cells.
* **Option B:** This option is incorrect because membranous nephropathy is a different condition characterized by the deposition of immune complexes on the glomerular basement membrane.
* **Option C:** This option is incorrect because minimal change disease is a different condition characterized by the loss of foot processes of podocytes without significant glomerular scarring.

**Clinical Pearl / High-Yield Fact**
FSGS is often associated with the development of nephrotic syndrome, characterized by heavy proteinuria, hypoalbuminemia, and edema. The condition is a common cause of end-stage renal disease (ESRD) and requires early recognition and treatment to prevent progression.

**Correct Answer: D.**