Chromosomes involved in adult polycystic kidney disease (APKD) –
**Core Concept**
Adult polycystic kidney disease (APKD) is a genetic disorder characterized by the growth of numerous cysts filled with fluid in the kidneys, leading to progressive kidney damage and impaired renal function. It is an autosomal dominant disorder, meaning a single copy of the mutated gene is sufficient to cause the disease.
**Why the Correct Answer is Right**
APKD is primarily caused by mutations in the PKD1 gene, which encodes for the polycystin-1 protein. This protein plays a crucial role in maintaining the normal structure and function of renal tubular epithelial cells, and mutations in the PKD1 gene disrupt this process. The PKD1 gene is located on the short arm of chromosome 16 (16p13.3). The PKD2 gene, located on chromosome 4 (4q21), is another gene associated with APKD, but it is less commonly mutated than PKD1.
**Why Each Wrong Option is Incorrect**
* **Option A:** Not applicable, as the question does not provide an option for chromosome 16.
* **Option B:** Not applicable, as the question does not provide an option for chromosome 4.
* **Option D:** Not applicable, as the question does not provide an option for chromosome 17.
**Clinical Pearl / High-Yield Fact**
It's essential to remember that APKD is an autosomal dominant disorder, meaning a single copy of the mutated gene is sufficient to cause the disease. This means that offspring of an affected parent have a 50% chance of inheriting the mutated gene.
**Correct Answer:** C. 16