**Core Concept**
Polycystic kidney disease (PKD) is a genetic disorder characterized by the growth of numerous cysts in the kidneys, leading to progressive kidney damage and eventual loss of renal function. The most common form of PKD is autosomal dominant polycystic kidney disease (ADPKD), which accounts for approximately 90% of cases.

**Why the Correct Answer is Right**
The correct answer will be related to a statement that is not true about PKD. PKD is primarily a disorder of the kidney, but it can also involve other organs such as the liver, pancreas, and brain. The cysts in PKD are typically filled with fluid and can grow to varying sizes, causing damage to the surrounding kidney tissue. The pathogenesis of PKD involves mutations in genes that code for proteins involved in cell-cell adhesion and cell polarity, such as PKD1 and PKD2.

**Why Each Wrong Option is Incorrect**
**Option A:** PKD is primarily a disorder of the liver.
* This is incorrect because while liver cysts can occur in PKD, the primary organ affected is the kidney.

**Option B:** The cysts in PKD are typically filled with blood.
* This is incorrect because the cysts in PKD are typically filled with fluid, not blood.

**Option C:** PKD is caused by a mutation in the BRCA1 gene.
* This is incorrect because PKD is caused by mutations in genes such as PKD1 and PKD2, not BRCA1.

**Option D:** PKD is an autosomal recessive disorder.
* This is incorrect because the most common form of PKD, ADPKD, is an autosomal dominant disorder.

**Clinical Pearl / High-Yield Fact**
It's essential to remember that PKD can also involve extrarenal manifestations, such as liver cysts, pancreatic cysts, and intracranial aneurysms. A high index of suspicion for PKD is crucial in patients with a family history of the disease or those who present with hematuria, hypertension, or renal failure.

**Correct Answer:** D. PKD is an autosomal recessive disorder.