The following are true about fibronectin nephropathy,except:
**Fibronectin Nephropathy**
**Core Concept**
Fibronectin nephropathy is a rare, familial form of glomerular disease characterized by the accumulation of fibronectin in the glomerular mesangium, leading to podocyte injury and proteinuria. It is often associated with mutations in the MUC1 gene, which codes for a high-molecular-weight glycoprotein that interacts with fibronectin.
**Why the Correct Answer is Right**
The disease is characterized by the deposition of fibronectin in the glomerular mesangium, which disrupts normal glomerular filtration and leads to proteinuria. The MUC1 gene mutation affects the function of the glycoprotein, leading to increased binding to fibronectin and its accumulation in the glomerulus. This results in podocyte injury and progressive kidney disease.
**Why Each Wrong Option is Incorrect**
* **Option A:** Not provided, skipping to Option B.
* **Option B:** Fibronectin nephropathy is indeed a rare disease, but it is not typically associated with a specific age group or sex predilection. However, the correct answer is not B, so I will skip to Option C.
* **Option C:** Fibronectin nephropathy is associated with mutations in the MUC1 gene, not the COL4A3 gene. The COL4A3 gene is associated with Alport syndrome, a different form of glomerular disease.
* **Option D:** Fibronectin nephropathy is indeed characterized by the accumulation of fibronectin in the glomerular mesangium, which leads to proteinuria. Therefore, Option D is not the correct answer.
**Clinical Pearl / High-Yield Fact**
Fibronectin nephropathy is a rare, familial form of glomerular disease that highlights the importance of genetic testing in the diagnosis of glomerular disease. A high index of suspicion is necessary to diagnose this condition, as it can be challenging to distinguish from other forms of glomerulonephritis.
**Correct Answer: C. Fibronectin nephropathy is associated with mutations in the COL4A3 gene.