Which autosomal recessive disorder results from a mutation on chromosome 7?
Solution
Correct Answer: Option B
The correct answer is Cystic fibrosis.
- Cystic fibrosis is an autosomal recessive disorder caused by mutations in the CFTR gene located on chromosome 7.
- This gene encodes the cystic fibrosis transmembrane conductance regulator protein, which functions as a chloride channel in epithelial cells.
- Mutations lead to defective chloride transport, resulting in thick, sticky mucus accumulation primarily in the lungs and digestive system.
- This causes symptoms such as chronic respiratory infections, pancreatic insufficiency, and malnutrition.
To clarify the other options:
- Sickle cell anemia is also autosomal recessive but results from a mutation in the HBB gene on chromosome 11.
- Phenylketonuria (PKU) results from mutations in the PAH gene on chromosome 12.
- Tay-Sachs disease is caused by mutations in the HEXA gene on chromosome 15.
Thus, the defining genetic feature of cystic fibrosis is its mutation on chromosome 7.
Reference: Robbins Basic Pathology, 10th Edition, Chapter on Genetic Disorders, p. 98-102
- Cystic fibrosis is an autosomal recessive disorder caused by mutations in the CFTR gene located on chromosome 7.
- This gene encodes the cystic fibrosis transmembrane conductance regulator protein, which functions as a chloride channel in epithelial cells.
- Mutations lead to defective chloride transport, resulting in thick, sticky mucus accumulation primarily in the lungs and digestive system.
- This causes symptoms such as chronic respiratory infections, pancreatic insufficiency, and malnutrition.
To clarify the other options:
- Sickle cell anemia is also autosomal recessive but results from a mutation in the HBB gene on chromosome 11.
- Phenylketonuria (PKU) results from mutations in the PAH gene on chromosome 12.
- Tay-Sachs disease is caused by mutations in the HEXA gene on chromosome 15.
Thus, the defining genetic feature of cystic fibrosis is its mutation on chromosome 7.
Reference: Robbins Basic Pathology, 10th Edition, Chapter on Genetic Disorders, p. 98-102
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