Question

Consider the following statements: Cystic fibrosis of the pancreas
1. Is an autosomal dominant disorder.
2. Is established by sweat sodium concentrations more than 80 mmol/L.
3. May produce neonatal small bowel obstruction.
4. Is associated with a dysfunction of all mucus secreting glands.
Which of these statements are correct?

• A. 2, 3 and 4
• B. 1, 3 and 4
• C. 1, 2 and 3
• D. 1, 2 and 4

Hint:

Remember cystic fibrosis is autosomal recessive, not dominant, even though its other features here are all true.

Answer 1

The Correct Option is A

This question checks four statements about cystic fibrosis of the pancreas, and we need to find which combination is true.

1. Autosomal dominant disorder: This is false, since cystic fibrosis is actually autosomal recessive, requiring two defective CFTR gene copies.
2. Sweat sodium more than 80 mmol/L: This is true, since an elevated sweat chloride/sodium test is the classic diagnostic test for this condition.
3. Neonatal small bowel obstruction: This is true, since thick meconium can cause meconium ileus in newborns with cystic fibrosis.
4. Dysfunction of all mucus secreting glands: This is true, since the CFTR defect disrupts chloride transport across essentially all exocrine mucus glands in the body.

Since only the inheritance pattern statement is false, the correct combination is statements 2, 3, and 4.

Let's summarize:

• Cystic fibrosis is autosomal recessive, not dominant.
• Its sweat test, bowel obstruction risk, and widespread mucus gland dysfunction are all true features.

So the correct statements are 2, 3 and 4.