**Core Concept**
Polycystic kidney disease (PKD) is a genetic disorder characterized by the growth of numerous cysts filled with fluid in the kidneys, leading to progressive kidney damage and impairment of kidney function. It's a common cause of end-stage renal disease and affects various organs and systems.

**Why the Correct Answer is Right**
Erythrocytosis, or an increase in red blood cell count, is not typically associated with polycystic kidney disease. In fact, patients with PKD often experience anemia due to the loss of erythropoietin-producing kidney tissue. Erythropoietin is a hormone that stimulates red blood cell production. **Option D** is incorrect because PKD does not cause an increase in red blood cell count; rather, it can lead to a decrease in red blood cell count.

**Why Each Wrong Option is Incorrect**
**Option A:** Hematuria, or blood in the urine, is a common feature of PKD due to the rupture of cysts and bleeding into the urinary tract.
**Option B:** Hypertension is a frequent complication of PKD, often resulting from the increased intrarenal pressure and vascular remodeling.
**Option C:** Renal failure, or end-stage renal disease, is a hallmark of advanced PKD, leading to progressive kidney damage and eventual loss of kidney function.

**Clinical Pearl / High-Yield Fact**
PKD can also affect other organs, such as the liver (autosomal dominant polycystic liver disease) and the pancreas, and can increase the risk of cardiovascular disease and cysts in other organs.

**✓ Correct Answer: D. Erythrocytosis**