True of autosomal dominant polycystic kidney disease I and II respectiely –
**Core Concept**
Autosomal dominant polycystic kidney disease (ADPKD) is a genetic disorder characterized by the growth of numerous cysts on the kidneys, leading to kidney enlargement and impaired renal function. ADPKD is caused by mutations in either the PKD1 or PKD2 gene, which encodes for polycystin-1 and polycystin-2, respectively.
**Why the Correct Answer is Right**
ADPKD I is caused by mutations in the PKD1 gene, which is located on chromosome 16 and is responsible for approximately 85% of ADPKD cases. This mutation leads to the formation of large cysts in the kidneys, which can cause kidney enlargement and impaired renal function. ADPKD II, on the other hand, is caused by mutations in the PKD2 gene, which is located on chromosome 16 as well but is responsible for a smaller percentage of ADPKD cases. The cysts in ADPKD II are generally smaller than those in ADPKD I.
**Why Each Wrong Option is Incorrect**
**Option A:** This option would be incorrect if it stated that ADPKD I is caused by mutations in the PKD2 gene, which is actually associated with ADPKD II. ADPKD I is primarily caused by mutations in the PKD1 gene.
**Option B:** This option would be incorrect if it stated that ADPKD II is caused by mutations in the PKD1 gene, which is actually associated with ADPKD I. ADPKD II is primarily caused by mutations in the PKD2 gene.
**Option C:** This option would be incorrect if it stated that both ADPKD I and II are caused by mutations in the same gene, such as the PKD1 or PKD2 gene. While both conditions are caused by mutations in these genes, they are associated with different genes.
**Option D:** This option would be incorrect if it stated that the location of the genes associated with ADPKD I and II are different, such as one being located on chromosome 16 and the other on a different chromosome. Both ADPKD I and II are associated with genes located on chromosome 16.
**Clinical Pearl / High-Yield Fact**
It's essential to remember that the PKD1 gene is responsible for approximately 85% of ADPKD cases, while the PKD2 gene is responsible for a smaller percentage. This knowledge can aid in the diagnosis and management of ADPKD.
**Correct Answer:** A. ADPKD I is caused by mutations in the PKD1 gene.