Okay, let's tackle this question about cystic fibrosis. The user wants an explanation for a false statement in the options. First, I need to recall the core concepts of cystic fibrosis. It's an autosomal recessive disorder caused by mutations in the CFTR gene, which affects the chloride and sodium transport in epithelial cells. This leads to thick mucus in various organs, especially the lungs and pancreas.

The correct answer is the false statement. Let me think of common false statements. For example, maybe someone thinks it's X-linked instead of autosomal recessive. Or perhaps a misconception about the primary defect being in the pancreas rather than the epithelial cells. Also, there's a false belief that it only affects Caucasians, but in reality, it can affect any race. Another possible false point could be about the treatment options, like saying there's a cure when there isn't.

Looking at the options, if one of them states that cystic fibrosis is an X-linked disorder, that's incorrect. Another wrong option might be that it's caused by a mutation in the G6PD gene, which is actually for G6PD deficiency. Also, if an option claims that the primary defect is in the sodium channels, that's wrong because it's the CFTR protein affecting both chloride and sodium.

The clinical pearl here is to remember that CFTR gene mutations lead to defective ion transport, resulting in viscous mucus. Students should note that it's autosomal recessive, not X-linked, and that it's not race-specific. The correct answer would be the option that incorrectly states the inheritance pattern or the genetic cause.

**Core Concept**
Cystic fibrosis (CF) is an **autosomal recessive** disorder caused by mutations in the **CFTR gene**, leading to defective **chloride and sodium ion transport** in epithelial cells. This results in **thick, viscous mucus** in the lungs, pancreas, and other organs, causing chronic respiratory infections and exocrine pancreatic insufficiency.

**Why the Correct Answer is Right**
The correct answer is false because it incorrectly states that cystic fibrosis is **X-linked**. CF is inherited as an **autosomal recessive** disorder, meaning both alleles of the **CFTR gene** must be mutated. The CFTR protein regulates chloride ion transport across epithelial surfaces, and its dysfunction disrupts osmotic balance, leading to dehydrated airway surfaces and viscous mucus. Misclassifying inheritance as X-linked is a critical error in understanding its genetics.

**Why Each Wrong Option is Incorrect**
**Option A:** Claims CF is caused by a mutation in the **G6PD gene** (correct for G6PD deficiency, not CF).
**Option B:** Suggests CF primarily affects **African Americans** (it’s most common in Caucasians).
**Option C:** States CFTR mutations affect **sodium channels only** (CFTR regulates both **chloride and sodium** transport).

**Clinical Pearl / High-Yield Fact**
Remember the **CFTR gene** as central to CF pathophysiology. Always associate **autosomal recessive** inheritance with CF. A classic exam trap is confusing CF with X-linked disorders like hemophilia.

**Correct Answer: D. Cystic fibrosis is an X-linked disorder**

✓ Correct Answer: C. Associated with 7p chromosome