Question

Which genetic disorder causes the body to produce unusually thick mucus in the lungs and intestines?

• A. Hemophilia
• B. Down syndrome
• C. Cystic fibrosis
• D. Sickle-cell disease

Hint:

Cystic Fibrosis is an autosomal recessive disorder.
The defective CFTR channel leads to dehydration of mucus on cell surfaces, which causes the mucus to become thick and sticky.

Answer 1

The Correct Option is C

Step 1: Understanding the Concept:
Genetic disorders can arise from chromosomal abnormalities or single-gene mutations.
These mutations disrupt biochemical pathways, leading to characteristic clinical phenotypes.
Detailed Explanation:
Let us analyze each of the options:
- Hemophilia: A sex-linked recessive disorder characterized by a deficiency in blood clotting factors (Factor VIII or Factor IX), leading to prolonged bleeding. It does not affect mucus production.
- Down Syndrome: A chromosomal disorder caused by trisomy of chromosome 21, resulting in developmental delays and distinct physical features. It does not cause thick mucus.
- Cystic Fibrosis (CF): An autosomal recessive genetic disorder caused by mutations in the CFTR (Cystic Fibrosis Transmembrane Conductance Regulator) gene on chromosome 7.
The CFTR protein functions as a channel that transports chloride ions across epithelial cell membranes.
When this channel is defective, the transport of salt and water into and out of cells is disrupted.
This leads to the production of abnormally thick, sticky mucus in the respiratory, digestive, and reproductive tracts.
The thick mucus plugs ducts and airways, particularly in the lungs and pancreas, causing breathing difficulties and digestive issues.
This matches the description given in the question.
- Sickle-Cell Disease: An autosomal recessive disorder of hemoglobin synthesis that causes red blood cells to become crescent-shaped, leading to anemia and vaso-occlusive crises.

Step 2: Final Answer:
The genetic disorder that causes the production of unusually thick mucus in the lungs and intestines is Cystic fibrosis.