Chronic exposure to aflatoxin B1 is a major risk factor for hepatocellular carcinoma. This carcinogen classically causes a specific G:C to T:A transversion in the TP53 gene at codon 249, resulting in an arginine to serine substitution. This type of mutation is best described as a:
- A Missense mutation ✓
- B Frameshift mutation
- C Nonsense mutation
- D Silent mutation
Correct answer: A. Missense mutation
Explanation
The aflatoxin-associated TP53 R249S mutation changes the amino acid sequence, making it a missense mutation. C nonsense mutation introduces a premature stop codon. C frameshift mutation results from insertions or deletions that alter the reading frame. C silent mutation changes the nucleotide sequence without altering the encoded amino acid.
Reference: Robbins and Cotran Pathologic Basis of Disease, 10th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
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